Each year, we hear that people are gaining weight and that chronic health problems like obesity, heart problems, and diabetes are on the rise.  It’s commonplace to ascribe these trends to personal lifestyle choices, such as the lack of exercise and diet, as well as the increasingly pervasive nature of fast food and processed, high-sugar foods.

However, there may be additional risk factors that are harder to control, such as genetics, and—as  a provocative new article in PLoS One (open access) suggests—birth order.  Specifically, first-born children might be more prone to these kinds of chronic health issues later in life:

Recent work has suggested that birth order may be a non-modifiable risk factor for obesity. Current evidence suggests that first-born infants grow faster than later-born infants. Dunger et al. suggest that the in-utero growth of first-born babies may be restrained as they have lower birth weight and accelerated post-natal catch-up growth, both of which are risk factors for obesity and cardiovascular and metabolic diseases, in adult life. However, whether first-born individuals have elevated metabolic risk in adulthood remains unknown. A recent study found that first-borns had a 4-fold risk of increased fat mass in early adulthood compared to later-borns. Neither of these studies evaluated the magnitude of metabolic risk induced by such greater weight and adiposity.

…Here we investigate the associations of birth-order with metabolic phenotype in early adulthood using data from a birth cohort of Brazilian young men. We tested two hypotheses. First, we wanted to confirm that first-born status was associated with low birth weight and faster infant growth. Second, we tested the hypothesis that metabolic risk was increased in first-borns compared to later-borns.

What did they find? What implications might their work have for public health given the kinds of global population changes we expect over coming decades?

Some results (excerpts):

• After adjusting for family income, maternal education, household assets score and maternal smoking in pregnancy, first-borns had significantly lower mean birth weight.
• First-borns also showed faster weight gains during infancy and had greater mean height and weight at 43 months.
• This greater weight and height tracked into early adulthood, with first-borns being significantly taller and heavier than later-borns.
• Total cholesterol and low-density lipoproteins were higher among first-borns.
• Our analysis suggests that low birth weight does not itself explain the increased metabolic risk associated with birth order. Rather, rapid post-natal weight gain appears most important, although such rapid growth is itself a response to low birth weight. Broadly similar growth patterns have been linked to the occurrence of type 2 diabetes and coronary events in adults.

So why do these patterns happen?  Here is their hypothesis:

The lower birth weight of first-borns can be attributed to materno-fetal physiological interactions. Following implantation, cells from the outer layer of the blastocyst, known as trophoblast, invade the maternal endometrium and alter the structure of the arteries that transfer blood to the placenta. Such modification decreases maternal resistance and increases placental blood flow. These changes then impact on the placental dynamics of subsequent pregnancies, such that second-born neonates are well known to have higher average birth weight than first-borns. Dunger et al. suggested that first-born children have higher glucose levels compared to later-borns, an effect most likely due to the combined effect of insulin resistance due to the increased adiposity and to the possible in utero programming of the insulin glucose axis. Thus, the increased adult body weight and adiposity of first-borns is likely to be induced at least in part by the maternal constraint of intra-uterine growth. However, other mechanisms may also be important. There is preliminary evidence in animals and in humans, that the novel experience of the first pregnancy could raise the level of apprehension in primigravid women, thereby potentially affecting the growth of the foetus via modulation of the vascular and endocrine functions of the feto-placental unit. Maternal emotional stress is an established risk factor for low birth weight, intrauterine growth retardation, preterm delivery and still-birth. Specifically, circadian cortisol secretion pattern appears to be distinctive in primiparous women and an alteration of the hypothalamus-pituitary axis (HPA) function could modify maternal glucocorticoids levels and affect foetal development. Possible mechanisms for birth-order effects on foetal growth merit further research.

And what potential implications might this have for the health of the global human population as we approach 9 billion people on the planet by 2050 and move through demographic transitions, such as reduced family sizes (emphasis mine)?

Our findings contribute to understanding of the early origins of adult disease. Our data show that a demographic factor relevant to all human populations can generate variability in both early growth and later metabolic risk. These findings also have important implications for understanding the increasing prevalence of the metabolic syndrome worldwide, where many populations are undergoing demographic change in response to economic development. Globally, there is a trend towards lower fertility rate, such that increasing proportion of individuals will be first-borns. In Brazil, for example, the average number of children per women (total fertility rate) dropped from 6.0 in 1960 to 1.8 currently.

They conclude with several important qualifications:

[A] number of questions still merit attention. For example, studies should describe in more detail the growth patterns that appear to lead to elevate metabolic risk, and identify the optimal time periods for intervention. Studies should also clarify the relative contribution of different possible underlying mechanisms (growth patterns, psychological factors) to the effects that we observed in these samples. Third, more research is required to establish the magnitude of the effect, whether it is similar in men and women, and whether it amplifies with age, as adverse metabolic profile consolidates. In these samples of young adults, the magnitude of the effect was relatively small, but degenerative diseases are expressed primarily from middle age and early-life effects tend to become more important through adulthood.

Siervo, M., Horta, B., Stephan, B., Victora, C., & Wells, J. (2010). First-Borns Carry a Higher Metabolic Risk in Early Adulthood: Evidence from a Prospective Cohort Study PLoS ONE, 5 (11) DOI: 10.1371/journal.pone.0013907

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Photo credit: portfolium

The Atlantic is featuring an interesting back-and-forth between rancher and author, Nicolette Hahn Niman, and philosopher Adam Phillips.

Niman: Dogs Aren’t Dinner: The Flaws in an Argument for Veganism

Phillips: Dogs Aren’t Dinner–and Pigs Shouldn’t Be Either

This debate focuses on whether eating pigs carries the same ethical considerations as eating dogs.   But it has deeper roots in a centuries-old debate about objective vs. relative moral truths in our world.

Update:

For a current example of how this deeper debate is playing out, check out Sam Harris’ latest book, The Moral Landscape: How Science Can Determine Human Values.

For good examples of the philosophical foundations of this debate, read Anderson, Sen, Nussbaum, and Appiah.

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Photo credit: nao-cha

In the Policy Forum of today’s issue of Science, a research team that includes recent Nobel laureate, Elinor Ostrom, issued a call for innovative interdisciplinary approaches to confronting major environmental challenges:

Tremendous progress has been made in understanding the functioning of the
Earth system and, in particular, the impact of human actions. Although this
knowledge can inform management of specific features of our world in transition, societies need knowledge that will allow them to simultaneously reduce global environmental risks while also meeting economic development goals. For example, how can we advance science and technology, change human behavior, and influence political will to enable societies to meet targets for reductions in greenhouse gas emissions to avoid dangerous climate change? At the same time, how can we meet needs for food, water, improved health and human security, and enhanced energy security? Can this be done while also meeting the United Nations Millennium Development Goals of eradicating extreme poverty and hunger and ensuring ecosystem integrity?

They identified what they call five grand challenges:

(1) Improve the usefulness of forecasts of future environmental conditions and their consequences for people.

(2) Develop, enhance, and integrate observation systems to manage global and regional environmental change.

(3) Determine how to anticipate, avoid, and manage disruptive global environmental change.

(4) Determine institutional, economic, and behavioral changes to enable effective steps toward global sustainability.

(5) Encourage innovation (and mechanisms for evaluation) in technological, policy, and social responses to achieve global sustainability.

And their concluding message resonates with much of what I have been writing about at Global Change (emphasis mine):

These grand challenges provide an overarching research framework to mobilize the international scientific community around a focused decade of research to support sustainable development in the context of global environmental change. … Research dominated by the natural sciences must transition toward research involving the full range of sciences and humanities. A more balanced mix of disciplinary and interdisciplinary research is needed that actively involves stakeholders and decision-makers.

Reid, W., Chen, D., Goldfarb, L., Hackmann, H., Lee, Y., Mokhele, K., Ostrom, E., Raivio, K., Rockstrom, J., Schellnhuber, H., & Whyte, A. (2010). Earth System Science for Global Sustainability: Grand Challenges Science, 330 (6006), 916-917 DOI: 10.1126/science.1196263

Related posts:

From the Environmental Literacy in Higher Education series:

• Overview
• Part 1: What a changing world means for our graduates
• Part 2: Understanding the cultural context of environmental literacy
• Part 3: Framing contemporary problems
• Part 4: making it happen

From the Why Don’t People Engage Climate Change? series:

• The diversity of values held by conservation scientists and why this matters
• The ultimate cause of social disparity in preventative health behavior may be rooted in environmental harm
• Extreme climate and the vulnerability of least-developed countries
• Ecosystem stewardship: sustainability strategies for a rapidly changing planet
• Chicago 1995: How social disparities lead to environmental disasters
• “Can Biotech Food Cure World Hunger?”

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Image credit: woodleywonderworks

There have been several critiques of geoengineering as a climate mitigation tool.  Two of the most incisive, in my opinion, come from science and ethics.

The first is a 2007 paper in PNAS by Matthews and Caldeira showing that if we establish aerosol clouds or space reflectors while doing nothing to reduce carbon emissions, we run the risk of catastrophic rates of warming (2-4 degrees C per decade) if these systems were to fail.

The second is a recent piece in Slate by my colleague, Dale Jamieson, who argued that there is no moral and legal authority to know how and when to deploy geoengineering or by how much.

One proposed geoengineering tool is fertilizing the world’s oceans with iron.  The premise behind this idea was developed by John Martin in 1990, who is often quoted as saying something like, “Give me a tanker of iron, and I’ll give you an ice age.” Micronutrients like iron and zinc are extremely limiting to phytoplankton growth in the open ocean—orders of magnitude moreso than nutrients we typically think of in common fertilizers, like nitrogen and phosphorus.  Dumping iron into the oceans has been shown to stimulate algal blooms, and the creation of this biomass consumes CO2 from the surface waters and atmosphere, thereby helping to mitigate rising CO2 from fossil fuels.  In theory, some of this biomass should sink to the deep ocean where it is sequestered for centuries, but this has yet to be shown definitively on a wide scale.

In a forthcoming paper in the Proceedings of the National Academy of Sciences, Mary Silver and colleagues show that there is another potential risk of geoengineering resulting from ocean iron fertilization…

It turns out that some of the phytoplankton stimulated by these iron additions secrete toxins in the water at concentrations that are potentially harmful to marine life:

Near-surface waters ranging from the Pacific subarctic (58°N) to the Southern Ocean (66°S) contain the neurotoxin domoic acid (DA), associated with the diatom Pseudo-nitzschia. Of the 35 stations sampled, including ones from historic iron fertilization experiments (SOFeX, IronEx II), we found Pseudo-nitzschia at 34 stations and DA measurable at 14 of the 26 stations analyzed for DA. Toxin ranged from 0.3 fg·cell−1 to 2 pg·cell−1, comparable with levels found in similar-sized cells from coastal waters. In the western subarctic, descent of intact Pseudo-nitzschia likely delivered significant amounts of toxin (up to 4 μg of DA·m−2·d−1) to underlying mesopelagic waters (150–500 m). By reexamining phytoplankton samples from SOFeX and IronEx II, we found substantial amounts of DA associated with Pseudo-nitzschia. Indeed, at SOFeX in the Antarctic Pacific, DA reached 220 ng·L−1, levels at which animal mortalities
have occurred on continental shelves. Iron ocean fertilization also occurs naturally and may have promoted blooms of these ubiquitous algae over previous glacial cycles during deposition of iron-rich aerosols. Thus, the neurotoxin DA occurs both in coastal and oceanic waters, and its concentration, associated with changes in Pseudo-nitzschia abundance, likely varies naturally with climate cycles, as well as with artificial iron fertilization. Given that iron fertilization in iron-depleted regions of the sea has been proposed to enhance phytoplankton growth and, thereby, both reduce atmospheric CO2 and moderate ocean acidification in surface waters, consideration of the potentially serious ecosystem impacts associated with DA is prudent.

Mary W. Silvera, Sibel Bargu, Susan L. Coale, Claudia R. Benitez-Nelson, Ana C. Garcia, Kathryn J. Roberts, Emily Sekula-Wood, Kenneth W. Bruland, and Kenneth H. Coale (2010). Toxic diatoms and domoic acid in natural and iron enriched waters of the oceanic Pacific Proceedings of the National Academy of Sciences : 10.1073/pnas.1006968107

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Photo credit: emdot

In an interesting new article in Climatic Change, Christopher Doughty and colleagues at Stanford consider whether raising crop albedo (reflectivity) could decrease solar  absorption at the Earth’s surface and cool regional climates.  One might consider this a kind of climate “bio”engineering.

How could you do this, and would it work?

Many desert plants have hair-like projections that reflect excess energy and keep the leaves cool.  As the authors suggest, perhaps crops could be developed/switched such that agricultural landscapes become more reflective:

Agricultural scientists have modified crop morphology with concomitant
increases in albedo. Leaf pubescence in soybeans was increased fourfold over normal varieties to increase crop water use efficiency, thereby increasing surface albedo by ∼0.01. Switching from a potential biofuel crop such as corn (albedo: 0.20–0.23) or soybean (albedo: 0.21) to a higher albedo potential biofuel crop, such as sunflower (albedo: 0.24–0.30) can increase surface albedo by ∼0.06.

Using a computer to simulate how climate is affected by changing plant albedo, here’s what they found:

Simulations indicate that planting brighter crops can decrease summertime maximum daily 2 m air temperature by 0.25◦C per 0.01 increase in surface albedo at high latitudes (>30◦).

Based on the numbers shown above, a 6% rise in albedo would be enough to cool regional climate by 1.5◦C.

However, there are a few challenges:

(1) It turns out that when you plant high albedo crops a low latitudes close to the equator, the increased reflectivity means that plants don’t absorb as much sunlight, they don’t heat up as much, and they don’t lose as much water to the atmosphere via their leaves. In the computer model, this leads to less cloud cover and more sunlight reaching the soil surface, which heats air temperatures and counteracts any cooling effect of the more reflective leaves.

(2) When they looked at different varieties of soybeans, they could only muster a 1.6% increase in albedo based on differences in existing types, meaning that there’s only about a 0.4◦C cooling possible by changing from a less-hairy to a more-hairy soybean crop.

Bottom line:  Although substantial regional cooling could be achieved at high latitudes from switching crop types, the authors argue that it’s unlikely that we will be able to significantly offset future warming with the kinds of crop albedo changes currently available.

Doughty, C., Field, C., & McMillan, A. (2010). Can crop albedo be increased through the modification of leaf trichomes, and could this cool regional climate? Climatic Change DOI: 10.1007/s10584-010-9936-0

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Photo credit: autan

When CO₂ from fossil fuels accumulates in the atmosphere, some of it dissolves into the oceans where it reacts with water to form a weak acid (H₂CO₃) —carbonic acid— that lowers seawater pH and makes it increasingly difficult for corals and other calcitic organisms to form their calcium carbonate (CaCO₃) skeletons.

A new study in the Proceedings of the National Academy of Sciences by Rebecca Albright and colleagues suggests that the negative effects of ocean acidification don’t stop with adult organisms.  The colonization and establishment of juvenile corals appear to be severely impacted.  They studied a common coral found in the Caribbean—Acropora palmata (elkhorn coral, which is not the same as the staghorn coral species pictured above).

A snapshot of their results:

• When corals were grown in seawater with elevated CO₂ to simulate mid- and late-century emissions trends, they found a 52% and 73% decline in coral settlement success, respectively.
• For corals that settled and started growing, they found that the mid- and late-century CO₂ levels reduced early growth by 39% and 50%, respectively.

This is potentially very bad news because if you shut down the capacity for new corals to establish, you reduce the ability of coral reef systems to persist in the face of disturbances like hurricanes, wave action, nutrient pollution, bleaching, and disease.

Rebecca Albright, Benjamin Mason, Margaret Miller, and Chris Langdon (2010). Ocean acidification compromises recruitment success of the threatened Caribbean coral Acropora palmata Proceedings of the National Academy of Sciences

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Photo credit:  One of my photos from the Great Barrier Reef.  Check out my entire collection at Flickr.

In a forthcoming article in the Proceedings of the National Academy of Sciences, Patric Allard and Monica Colaiácovo use a nemotode (round worm) system to explore how BPA damages genetic processes in animals.

BPA ranks among the highest production volume chemicals with a global annual production scale of ≈4 million metric tons. It is commonly used in the manufacture of several polymers, including polycarbonate and epoxy resins. Thus, BPA is found in a variety of items such as plastic bottles, the lining of both food and beverage cans, and dental sealants. Consistent with its widespread presence, urinary BPA is detected in >90% of the population in the United States. Higher levels of urinary BPA have been correlated with cardiovascular diseases and diabetes and may be associated with an increased risk for miscarriages.

Their results?

Using these conditions, we observed a sixfold reduction in the mean number of eggs laid (increased sterility) and a dramatic increase in embryonic lethality (97.3%; n = 333) in worms exposed to 1 mM BPA compared with vehicle. Furthermore, none of the rare larvae observed either reached adulthood or survived after 3 d in culture (100% larval lethality). Taken together, these phenotypes indicate that BPA impairs C. elegans reproduction and are suggestive of errors in chromosome segregation.

Why was this?  They found that worms exposed to BPA had dysfunctional DNA repair mechanisms that ordinarily fix breaks in genetic material.  It turns out that BPA exerts hormone-like effects and turns off the gene that makes the DNA repair proteins.

Without these repairs, the animals were not able to produce eggs (in an important cell division process called meiosis) with normal genetic material.  This led to incorrect chromosome alignment and separation in the cell division of embryonic worms.

Bottom line:  Exposure to BPA caused these worms to become sterile and exhibit elevated emrbyonic mortality.

There’s always a challenge in using lab animal models to extrapolate to human health.  One of the main criticisms of these kinds of studies is that the exposure concentrations are different than what people are experience on a daily basis.  The authors address this (emphasis mine):

We examined the internal levels of BPA following our exposure protocol and found that worms contained on average 2 μg/g of unconjugated BPA. These levels were within the range or lower than the internal free BPA levels detected in maternal kidneys, liver, and uterus, as well as in fetal liver and total fetal homogenate of pregnant rats perfused with a single dose of BPA at 10 mg/kg. Data on nonblood tissue levels of BPA both in rodent models and in humans are scarce and intraorgan concentrations in the BPA study on mouse meiosis were not measured, making direct exposure comparison difficult. However, it is likely that both our results and those of Susiarjo and colleagues represent the reproductive outcome following elevated BPA exposure. Therefore, our studies bear relevance to occupational exposure studies in humans, and particularly to fetal and neonate exposure levels, as suggested by the up to 10 times higher levels of BPA detected in premature infants in neonatal intensive care units.

Patrick Allard and Monica P. Colaiácovo (2010). Bisphenol A impairs the double-strand break repair machinery in the germline and causes chromosome abnormalities Proceedings of the National Academy of Sciences : 10.1073/pnas.1010386107

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Photo Credit: thesoftlanding

Here’s an interesting idea:  Get a bunch of people writing about environmental disasters to help raise awareness about what these are like (and may become) and to spur planning efforts for preventing/dealing with them.  That’s the latest from io9:

We can’t prevent environmental disasters without preparing for them. That’s why io9 is going to pay $2000 each to two people who write the best stories about environmental disaster. It’s io9′s Environmental Writing Contest – for science fiction and non-fiction.

io9 is looking for stories that deal with environmental disaster, whether caused by random asteroid impacts or oil drilling accidents. We believe that the first step to solving planet-scale problems is to assess, honestly and critically, what it would mean to experience such a disaster. We need mental models that can help policy-makers, researchers, and individuals prepare for the kinds of cataclysmic events that have occurred regularly throughout Earth’s history.

We’re holding this contest to reward people for coming up with ideas that could help avert the next Deepwater spill and Pacific garbage gyre – or help people prepare better for the next Indian Ocean tsunami and Haiti earthquake. Storytelling is a powerful tool. We want you to use it well.

Our awesome team of judges includes Elizabeth Kolbert (The New Yorker’s environment reporter), Paolo Bacigalupi (author of Ship Breaker and Windup Girl), and Jonathan Strahan (editor of the Eclipse anthologies), as well as others to be announced.

Interested?  The contest rules can be found at the link above.

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Photo credit:  Reinante El Pintor de Fuego

]]> http://www.globalchangeblog.com/2010/11/writing-about-disasters-as-an-environmental-literacy-tool/feed/ 0 http://www.globalchangeblog.com/2010/11/post-election-political-reality-part-iii/ http://www.globalchangeblog.com/2010/11/post-election-political-reality-part-iii/#comments Sun, 07 Nov 2010 17:27:51 +0000 Phil Camill http://www.globalchangeblog.com/?p=5011 In Throwing the Bums Out for 140 Years, David Kennedy adds a historian’s touch to the thread we have been developing since Thursday—wild swings in recent elections and the inability of the federal government to either confront or gain traction on tough social and environmental challenges:

Explanations for our current political volatility abound: toxic partisanship, the ever more fragmented and strident news media, high unemployment, economic upheaval and the clamorous upwelling of inchoate populist angst.

But the political instability of our own time pales when compared with the late 19th century. In the Gilded Age the American ship of state pitched and yawed on a howling sea of electoral turbulence. For decades on end, “divided government” was the norm. In only 12 of the 30 years after 1870 did the same party control the House, the Senate and the White House.

…And yet there are features of the Gilded Age that suggest some disturbing parallels with our own time. Generations of American scholars have struggled to find a coherent narrative or to identify heroic leaders in that era’s messy and inconclusive political scene. The history books give us a succession of Lilliputian presidents often described as “bearded, bland and boring.”

…In the face of all those challenges, like our Gilded Age forebears, we have a political system that manages to be both volatile and gridlocked — indeed, it may be gridlocked not least because it is so volatile. And, like their 19th-century forebears, today’s politicians have great difficulty gaining traction on any of those challenges. Now as then, it’s hard to lead citizens who are so eager to “throw the bums out” at every opportunity.

…So perhaps the stasis of the Gilded Age and the stalemate of our recent years reflect not so much the defects of our political structures as the monumental scale of the issues at hand. From that perspective, “wave” elections mark a necessary stage of indecision, shuffling, avoidance and confusion before a fractious democratic people can at last summon the courage to make tough choices, the creativity to find innovative solutions, the will to take consequential action and the old-fashioned moxie to put the ship of state again on an even keel.

The opinion pages at the NY Times are lighting up with more analysis of the wild swings from one political party to another in recent elections.

Some argue that America lacks the political leadership to confront pressing  challenges and that the large swing to Democrats in 2008 and then to Republicans in 2010 is a desperate search by the voting public to find this leadership.

The Rauch piece provides a complimentary, but different, perspective and is especially interesting. It suggests that the polarization of the parties along ideological lines over the past 20 years has made single-party control of Washington particularly unstable because voters in the minority react negatively to the policies of the majority party.  Divided government, although messy in appearance, he argues, may be the more stable and effective form of federal governance for getting things done.

David Brooks:

Democrats have, at least temporarily, blown the opportunity they were given to connect with the industrial Midwest. Voters in this region face structural problems, not cyclical ones. Intensely suspicious of government, they are nonetheless casting about for somebody, anybody, who can revive their towns and neighborhoods.

…American politics are volatile because nobody has an answer for these people. They will remain volatile until somebody finds one.

Bob Herbert:

It would be easy to misread the results of Tuesday’s elections, and it looks as if the leaders of both parties are doing exactly that.

Neither the Democrats nor the Republicans are offering voters the kind of change that they seem so desperately to want. We’re getting mind-numbing chatter about balanced budgets and smaller government and whether Mitch McConnell and his gang can chase President Obama out of the White House in 2012.

What voters want is leadership that will help them through an economic nightmare and fix a country that has been pitched into a state of sharp decline. They long for leaders with a clear and compelling vision of a better America and a road map for getting there. That leadership has long been AWOL. The hope in the tumultuous elections of 2008 was that it would come from Mr. Obama and the Democrats, but that hope, after just two years, is on life support.

Tuesday’s outcome was the result of voters, still hungry for change, who either switched in anger from the Democrats to the Republicans or, out of a deep sense of disappointment, stayed home.

…Our leaders in Washington seem entirely out of touch with the needs, the hopes, the fears and the anxieties of the millions of Americans who are out of work, who are struggling with their mortgages or home foreclosures, who are skimping on needed medication in order to keep food on the table, and who lie awake at night worrying about what the morning will bring. No one even dares mention the poor.

What this election tells me is that real leadership will have to come from elsewhere, from outside of Washington, perhaps from elected officials in statehouses or municipal buildings that are closer to the people, from foundations and grass-roots organizations, from the labor movement and houses of worship and community centers.

Frank Rich:

You can’t win an election without a coherent message. Obama, despite his administration’s genuine achievements, didn’t have one. The good news — for him, if not necessarily a straitened country — is that the G.O.P. doesn’t have one either. This explains the seemingly irrational calculus of Tuesday’s exit polls. Voters gave Democrats and Republicans virtually identical favorability ratings while voting for the G.O.P. They gave Obama a slightly higher approval rating than either political party even as they punished him. This is a snapshot of a whiplashed country that (understandably) doesn’t know whose butt to kick first.

…In the 1946 midterms, the unpopular and error-prone rookie president Harry Truman, buffeted by a different set of economic dislocations, watched his party lose both chambers of Congress (including 54 seats in the House) to a G.O.P. that then moved steadily to the right in its determination to cut government spending and rip down the New Deal safety net. Two years after this Democratic wipeout, despite a hostile press and a grievously divided party, Truman roared back, in part by daring the Republican Congress to enact its reactionary plans. He won against all odds, as David McCullough writes in “Truman,” because “there was something in the American character that responded to a fighter.”

Jonathan Rauch:

A GRAND victory for Republicans in the 2010 midterm election? Yes, of course. But also no. In all three of the most recent earthshaking midterm elections — 1994, 2006 and now 2010 — the same candidate won: divided government.

…Divided government comes about when one party controls the White House and the other controls either or both chambers of Congress. Washington has been split between the parties for more than 21 of the past 30 years (the exceptions being 1993 and 1994, part of 2001, 2003 to 2006, and the past two years). The middle four of President George W. Bush’s eight years represented the longest stint of unified government in that span. Not at all coincidentally, they also saw his party’s support nosedive.

Consistently, when either party, never mind which, obtains total control, its popularity collapses and the voters take the first available opportunity to bring in the other side.

This is a relatively recent phenomenon. From the Great Depression until the Ronald Reagan years, the public had no problem with keeping Democrats in charge of Congress for decades, no matter which party held the White House. In those days, however, both parties were ideologically broad coalitions. Northeastern Republicans stood to the left of Southern Democrats, for example. Regardless of which party was in power, ideological diversity was assured, and like-minded politicians worked across party lines.

That changed, and changed in a big way, as the parties re-sorted themselves along ideological lines. Today, almost all Democrats are to the left of all Republicans. The result is that the system behaves very differently when one party is in control than when they share. So differently, in fact, that you can fairly say that the country has one Constitution with two distinct modes of operation.

In Mode 1 — unified government — the minority party in Washington, shut out of power, has every incentive to make the majority’s life difficult, and does so. Its partisans, with no stake in whether anything gets done in Washington, treat the government as if it were under control of an invading army.

…In Mode 2 — divided government — the dynamic is reversed. Both parties, responsible for governing, have a stake in success. Forced to negotiate and compromise, they drag policy toward the center, allowing moderates to feel represented instead of ignored. Most important, the country itself becomes more governable and meaningful laws stand a likelier chance of passage…

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Photo credit: Stephen Little