After months of shadow-boxing, several of the main contenders for the Republican nomination are declaring their hand. The race has already occasioned a weight of commentary, much inevitably misleading. One piece of conventional wisdom seems to me clearly incorrect: it is that Republicans, a docile and deferential lot, always nominate the candidate next in line.

When you examine the specifics, you find that most of these “next-in-liners” in the past came very close to losing at an early stage. Mitt Romney, who finished second in popular votes to John McCain in the 2008 race for the party’s nomination, is often identified as the frontrunner this time. But he gets only 17 per cent in the realclearpolitics.com average of recent national polls, and that tends to reflect name-identification rather than profound commitment. Mr Romney has a personal fortune and raised $10m in one day – but money, as he found last time, does not necessarily buy votes.

Another familiar rule is that Republican nomination fights tend to be between economic and cultural conservatives. This is not so much the case any more.