Let's Call the Whole Thing Off

As the federal government comes ever more unglued, I've been thinking about the idea of optimal political union, parallel to the economic topic of the optimal currency union. Economists, starting with Robert Mundell in the 1960s, have developed the theory of optimal currency unions, and while this theory has not eliminated problems, it provides an analytic and theoretical framework to evaluate policy choices. More recently, economists, including Alberto Alesina and Enrico Spolaore, applied economic tools to the question of optimal political union size. For a variety of reasons, I've come to suspect that the United States is bigger than optimal.

One way to consider this is to think about the two-party system. The first-past-the-post voting system used in most US elections, including all federal elections and most state and local elections, makes a two-party system almost inevitable, and within that system, candidates should and do try to stake out the political space that is closest to the center of the electorates' preferences. This sort of system does not work, however, in the US right now: across the South, Democrats cannot occupy that center ground, because the broad platform of the national Democratic party differs so sharply from the political views of the Southern electorate, and, similarly, Republicans cannot occupy that center ground on the coasts. While at a national level the US remains a finely balanced two-party system, the high correlation of political views with geography means that, on a local level, much of the country suffers under one-party systems.

As far as I can tell, this began with Nixon's Southern strategy, which triggered the slow, steady alignment of political party with political views. On the face of it, there's nothing wrong with having parties that are more homogeneous and that have sharper, more strongly defined views. I suspect that the US population has sorted itself by political viewpoint to some extent, which, combined with the steady improvement in gerrymandering techniques, means that most candidates for office face competition only from members of their own party.

This process has caused two unfortunate results: at the national level, moderates have become scarce, because moderates don't win primary elections; and most state and local governments have become one-party affairs. The extinction of moderate members of Congress means that the federal government lurches from one gridlock to the next, and I see no reason to hope that this will ever get better. I think evolution of local politics into one-party systems is also bad for the country, but I'll leave that for another rant.

What to do? I can't think of any realistic way to reform the US political system to address this problem. So, on to the unrealistic proposals. I grew up in the South in a family of Northern carpetbaggers and then moved north for college and stayed. Growing up in the South, steeped in the lingering ideology of secession, left me with a strong sympathy for the concept of secession. Surely the basic human right to self-determination should include the right to choose our own political unions. I can't help applying this framework to problems around the world: why should Flemings and Walloons be forced to pretend they are all happy Belgians? Why should Africa be cursed with the arbitrary borders that the European colonialists drew?

All this leads me to wonder whether perhaps the least bad of the unrealistic solutions to the US's political problems is to optimize the political union size. If the old Confederacy can't get along with the rest of the USA, why should they and we suffer? Yes, a libertarian theocracy is a contradiction, but, if that's what the residents of the CSA think they want, I prefer that they attempt that as a separate country than that they try to transform my country into one.

Now, how to get there? Perhaps secession was a simple issue in 1861, but it's not now. These days the US has a real federal government, with assets and obligations, and, as in any divorce, dividing them up would be complicated. Consider Texas as a starting point. Texas has a little under 10% of the US population (8.2%, according to the 2013 estimates). I think that implies that a hypothetical Republic of Texas gets about $1.4 trillion of the current $16.8 trillion US debt. I'm sure that the hypothetical supporters of the Republic of Texas would argue that they shouldn't take the debt with them, and they would be wrong.

There are other complicated issues related to assets and obligations. Lots of folks bought US bonds expecting that the full faith and credit of the United States stood behind them. With Texas's current high bond rating, transforming 8% of their bonds into Republic of Texas bonds wouldn't make much difference, but I don't think the Chinese investors would be so happy with a vault full of Republic of Mississippi bonds.

Most Texans have been paying into the Social Security system: how would that obligation get transferred? What about the hypothetical Texians' obligation to pay the Social Security benefits of the remaining 92% of the US population. 

Next, after the financial accounts, the question of who gets the house and the furniture. Who gets Big Bend National Park, and Yellowstone? As divorce questions go, Texas is much easier than, say, Alaska: because of the way that they became states (Texas an independent republic, Alaska as a territory), the US federal government owns only 1.8% of Texas, while it owns 62% of the Alaska (http://www.fas.org/sgp/crs/misc/R42346.pdf). For Alaska, that's a whole lot of assets to argue about. And the furniture: who gets all the F/A-18s? The USS Texas? The federal highways? Hoover Dam? The TVA?

Beyond arguing about who gets the silver and who gets the house, there's the question of who gets the kids, or, in this case, everyone? Would current residents of Texas be entitled to a US passport if they wanted one? Would US residents be entitled to emigrate to Texas? Would Texians and USians have reciprocal rights to work? What would the border look like? USA-Canada, circa 1980 (road signs announcing the border and little buildings here and there inviting folks to stop in for coffee)? USA-Mexico circa 2020 (fencing reaching the sky guarded by laser-armed robots)? What about sub-state level regions? Could Austin secede from Texas and rejoin the USA if Texas seceded from the USA? Beyond citizenship and residency, would Texas continue to use the US dollar? Would it inherit membership in NATO? NAFTA? The NCAA?

I have opinions about some of these issues, but I don't think I have definitive answers on most them, so I propose a cop-out: rather than amending the constitution to spell all of this out, I would propose an amendment to the US constitution that would create a clear but constrained process for secession, but that would require the seceding states to negotiate a divorce decree with Congress. Here's my first draft of the constitutional amendment:

Proposed Amendment to the United States Constitution

Any state, or any group of states, shall have the right to propose an Article of Secession to the United States Congress. This proposal shall take the form of a law duly passed through the normal legislative process in the state or states, subject to the further requirement that the Article, after being passed, be subject to approval through referendum by public vote, and shall be approved only if a majority of at least two-thirds of the votes cast and at least half of the eligible voters in each state proposing to secede vote in favor of the Article. Upon approval of the Article of Secession by the governments and peoples of the proposed seceding states, the United States Congress shall consider the proposal and vote on the Article within one calendar year. If the House of Representatives and the Senate each approve the Article by majority of at least two-thirds of eligible votes, the Article shall take force.

By requiring approval by Congress, this proposal puts the burden on secessionists to talk their way out of the Union, and perhaps that's too strong. I'm tempted to propose some mechanism through which a secession movement could force its way out, but I can't think of a way to do that that would prevent a "dead-beat dad" approach, in which the secession movement shirks its responsibilities to the USA on the way out.

Global warming, Bayes' Law, and Russell's Teapot

Suppose I wanted to demonstrate that there is not a small teapot floating between Earth and Mars (Russell's Teapot). I might formulate a null hypothesis, there is a teapot, and my alternative hypothesis, there is no teapot, and then get to work gathering data, perhaps by building a really big telescope to look for it. Russell's point, however, is that finding a teapot is so difficult that it would take a whole lot of data to refute the null hypothesis. Russell argued that this implied that we should reverse the null hypothesis to a lack of a teapot, putting the burden on teapot-believers to generate evidence in support of the teapot.

Shifting to a Bayesian approach, I would instead start by examining my prior beliefs about the likelihood that there is a small teapot floating through space. While I wouldn't assign a prior of 0, because I don't believe in ever assigning any event a prior probability of 0 (or 1), my understanding of the solar system and of teapots would lead me to assign a very low prior probability. Given the structure of the problem, observational data that did not show a teapot wouldn't change my probability assessment much, because of the low likelihood of finding a teapot, should one exist, while a picture of a teapot would increase my probability assessment quite a lot, although not to 1, because of the possibility of a false negative (like, for example, a faked photo).

So, how does this relate to global warming? First, a few claims for which there is approximately no reasoned disagreement:

• Water vapor, carbon dioxide, and other gases in the atmosphere increase the temperature of Earth by absorbing more outgoing radiation (generated by Earth) than incoming radiation (generated by the Sun). In the absence of an atmosphere, Earth would have a temperature about 30 degrees C below its current temperature. This is basic thermodynamics, and while most people (including myself) don't understand it well, as far as I know, nobody who does understand it disputes these basic claims.
• All else equal, higher carbon dioxide levels produce more greenhouse warming. Again, pretty simple thermodynamics.
• All else equal, warmer air contains more water vapor that colder air. Basic atmospheric chemistry.
• Human activity has increased the concentration of carbon dioxide in the atmosphere from less than 300 ppm in the (geologically recent) pre-industrial past to more than 390 ppm today.

The debate over the human contribution to global warming is about whether the observational evidence supports or refutes the projection that human activity has and will continue to increase global temperatures.

Viewed from the standard frequentist framework, the null hypothesis is that human activity has not contributed to global warming, and the alternative is that human activity has contributed to global warming (a one-sided test). Given the noisiness of the climate, and of our observations of it, refuting the null hypothesis is difficult, and we could easily find ourselves in a situation in which Florida is under water, Kansas is a desert, and the Arctic Ocean is navigable without ever having a enough evidence to refute the null hypothesis.

On the other hand, if we view this from a Bayesian perspective, we get a very different answer. We have a theory about the relationship between human activity, atmospheric carbon dioxide, and global temperature. We should start with a pretty strong prior belief that human activity will contribute to global warming. The observational evidence will then allow us to refine our predictions about this relationship, but the noise in the evidence will not lead us to conclude that nothing is happening. What's more, in a Bayesian framework, our understanding of the basic mechanisms shifts the burden of proof: given strong prior beliefs, it would take strong evidence of a lack of a relationship to change our beliefs, while noisy evidence will not change our beliefs much.