It may not be the economy, stupid.
Then again, James Carville's famous maxim about the 1992 presidential campaign might well be valid in 2012. But it's quite possible that on Election Day, voters' most urgent concerns -- economic or not -- will be driven by overseas events that neither President Obama nor his Republican opponent can predict or control.
Analysts, commentators and, yes, columnists will fill the days between now and November with sage assessments of the campaigns. Does Obama have the right strategy? Does Mitt Romney have the right message? Which party has the better ground game? Which candidate's loose-remark-of-the-day qualifies as a certified gaffe?
But it might be more pertinent to ask, for example, what the North Korean news agency meant Monday with its threat to reduce parts of Seoul to ash with a military attack "by unprecedented peculiar means and methods of our own style."
North Korea's apocalyptic rhetoric can usually be written off as bluster. But the Stalinist dynasty in charge of the world's most isolated country has an inexperienced young leader whose first attempt to cover himself in glory -- testing a provocative new long-range missile -- was a humiliating failure. Could Kim Jong Eun actually be thinking the unthinkable?
As Obama has made clear, our nation's geopolitical strategic focus is shifting from the Atlantic to the Pacific -- where American interests run into those of the other emerging global superpower, China. This is why anyone trying to predict the course of the U.S. election campaign ought to pay attention to the scandal and turmoil that have gripped the Chinese government at a delicate moment of transition.
The central fact is that one of China's most charismatic and powerful politicians -- Bo Xilai, until recently the Communist Party boss in Chongqing -- has been sacked. His wife is accused of murdering a shadowy British businessman who may have helped the couple transfer untold millions of ill-gotten dollars into illegal offshore accounts.
Why might any of this matter to U.S. voters? Because the scandal exposes the most serious threat to the Chinese government's legitimacy -- widespread corruption -- just as the hierarchy prepares to name a new president this fall. As a way of shoring up patriotic support, officials may be tempted to be more aggressive in pushing China's territorial claims in the South China Sea. The United States might feel compelled to push back. Then what?
There are other, more obvious international situations that could have a big impact on the presidential race -- beginning, of course, with the war in Afghanistan. Both Obama and Romney lag well behind the public mood, which is for bringing the troops home now. Both may be tempted to catch up.
Meanwhile, there will likely be mounting pressure to do something about the brutal war of repression being waged by Bashar Assad in Syria. There's also the possibility of an Israeli attack on Iran's nuclear facilities. It may not happen -- but if it does, there's plenty of political danger here for both campaigns.
And if the Carville dictum turns out to be right? Well, stock markets around the world swooned on Monday -- not because of anything U.S. officials said or did but because of events in Europe that made investors nervous. The Dutch government fell, after failing to win approval of new austerity measures, while French President Nicolas Sarkozy finished second in his bid for re-election and faces a runoff.
It may be that in 2012 it's the eurozone crisis, stupid. And there's nothing Obama or Romney can do about it.