In an interview before a rapt crowd at the Aspen Ideas Festival this July, Bill Clinton wound up a high-toned discussion about global philanthropy with some political-pro handicapping of the upcoming US presidential race. "On the facts now," he said, "the person most likely to win the Republican nomination is the former governor of Massachusetts, Mitt Romney—who would then be likely to lose the general election, as President Obama would win a second term."

With a twinkle, Clinton added that he also liked the glamorous, eccentric representative from Minnesota, Michele Bachmann, because "she has a lot of juice".

The specifics of Clinton's predictions were less important than the way he introduced each aspect of them: "On the facts now." Clinton, who launched his campaign against the first President Bush when most other Democrats had been scared off by Bush's overwhelmingly positive ratings after the Gulf War, understands very clearly how quickly the relevant "facts" for a political campaign can change.

No one can be sure whether the worrisome, "double-dip" style weakness in the US job market in mid-2011 will persist into the election year, making Obama's prospects much worse. Nor whether an external event will take the electorate by surprise—one that bolsters the incumbent, like the killing of Osama bin Laden, or one that crystallises an impression of fecklessness, as the Iranian hostage crisis did to Jimmy Carter 30 years ago or hurricane Katrina did to George W. Bush's Republican party in 2006. Nor how candidates will hold up through the surprisingly important and arduous process of a year's worth of campaigning under non-stop media scrutiny.

While economic and political fundamentals matter most in campaign, in retrospect, minor mistakes or misjudgments in campaign strategy may have made the difference in the hair's-breadth presidential campaigns of 1948 and 1960, in 1968 and 1976 (both of which became very close at the end), in 1980 and 1992 and of course 2000.

So whatever we say is "on the facts now". On that basis however, there is one candidate whose position and prospects deserve particular attention outside the United States. That is Jon Huntsman jnr—Mandarin-speaker, Mormon, heir to a family industrial fortune worth billions, campaign chairman for John McCain in 2008, former governor of Utah, and, of great political and substantive relevance, for two years the Obama Administration's ambassador in its most important diplomatic posting, Beijing.

On the facts now, Huntsman is a more "interesting" candidate in theory than he is in demonstrated electoral significance. Bill Clinton said he liked him: "He just seems like a real guy, with his family." That family includes five biological children and two adopted ones, a little girl from China and one from India. And Huntsman is this cycle's winner of the "media primary", as the candidate whose press coverage until now most outstrips his financial and opinion-poll support. If, as currently seems likely, he finishes somewhere behind Romney (and is not the vice-presidential nominee, given the political imbalance of a two-Mormon ticket), what might his campaign illustrate? These points:

1. The surprising political insignificance of China.

Anyone who talks or writes about America's strategic and economic future underscores the crucial importance of China: China as partner; China as rival; China as example; China as caution. Opinion polls suggest that China's recent decades of economic miracle have captured the American public's attention. Some people blame China for "cheating" or "stealing jobs"; others fear that it is buying up the world; others see it as a site of future opportunity.

But politically, it seems, none of this matters. If it did, Huntsman—as the only candidate with any meaningful international experience, notably in China—would shoot to the head of the Republican ranks. There he would match his prescription for the right mixture of engagement and confrontation in dealing with China, against the policies of the man who appointed him ambassador, Barack Obama. Should Huntsman unexpectedly become the nominee, China policy would be a fascinating part of the general election campaign. But the long history of presidential politics suggests that in 2012, as in most previous years, China will matter a lot to America's prospects, and very little in the election itself.

2. The depressing political importance of the irrational.

What is one of Huntsman's major obstacles within his own Republican party? His religion. The heavily Mormon state of Utah is the most Republican state in the union, and Mormon interest groups have played a major role in national efforts against same-sex marriage and for other conservative causes. Even so, many of the fundamentalist Christians who play an increasing role in Republican politics believe, as a matter of doctrine, that Mormons are technically not Christians, and therefore are politically suspect. Democratic voters are more likely to disagree with mainstream Mormon positions than Republicans, but polls consistently show that larger proportions of Republicans say they would not vote for a Mormon on strictly religious grounds. This is entirely apart from those Republicans who have pronounced Huntsman unacceptable because he accepts the reality of climate change and supports same-sex civil unions (though not full-fledged gay marriage).

Thus, the better Huntsman does with this year's Republican electorate, the more heartening the sign of voters judging on something more than reflex. But wait ... the likely winner, Romney, is also a Mormon? How could that be? This leads us to:

3. The consistent Republican emphasis on "taking turns."

The Democratic party has frequently put forward "surprise" presidential candidates—those who come out of the relative wilderness to command attention a year or so before the election. Some lost (McGovern in 1972, Dukakis in 1988); some won (Carter in 1976, Clinton in 1992, Obama in 2008). The Republican party almost never does this. Its electors give heavy preference to the candidate whose "turn" it is. Romney is the leading candidate this time, largely because he ran a strong (though losing) campaign against John McCain four years ago. It had been McCain's turn in 2008 because he had been runner-up to George W. Bush back in 2000.

So if Jon Huntsman does not win this time? He is still worth watching, because eventually it could be his turn.