As a person who lives in America, works in opinion research and is interested in, you know, “politics,” I found this article by Nate Silver in the NYT an absolute goldmine.

He breaks down the 2012 US presidential election into four broad scenarios and, based on current polling data and some solid-sounding political science, weighs up the chances of the opposing candidates in each of them.

The two dimensions that give rise to the four scenarios are the state of the economy and the type of candidate the Republican Party selects to face Obama. Basically, the economy could either be flat or modestly improving, and the Republican candidate could be the moderate(ish) Mitt Romney or someone else who would most likely be more deeply conservative (Herman Cain, Rick Perry, Michele Bachmann… Rick Santorum? Still possible I guess).

In sum, if the economy fails to grow then Obama’s chances are less than 50% whoever the candidate is – although Romney’s chances would be much greater than the more conservative candidate’s. If the economy improves, Obama becomes the favourite whoever the opposition, but is a much stronger favourite if the Republican is a deep conservative. The two extreme cases are Romney+bad economy, in which the chances of an Obama victory are about one in six; and [conservative candidate]+good economy, in which the Republican’s chances are also one in six.

At the time the article was written, Obama’s overall chances in the election looked about 50-50 as it was pretty impossible to assign anything other than equal probabilities to all the scenarios. However as the Republican nomination debates have gone on, it has become clearer that none of the alternatives to Romney are really viable candidates, so for him not to end up as the candidate now would require a rather surprising intervention – either from a totally new candidate, or from an existing candidate who has been overlooked so far (Santorum again??). Which pushes the odds against Obama, as even with an improving economy, Romney’s chances don’t look all that bad (Silver says about 40%). Grim huh?