There are three main reasons for the delay: The intense focus on the 2010 midterms; the risks of starting too early; and, especially for the best-prepared candidate, Romney, a paralyzing fear of failure in Iowa.

In a sense, the incentives this year are reversed: candidates have better reasons to publicly hold off on declaring their candidacy than to try to gain an early foothold.

Unlike in 2006, when anxious Republicans were already casting about for a successor to President George W. Bush and bracing for congressional losses, GOP officials from the Capitol to the precinct level are focused on the November’s elections — and the prospect of retaking the House and Senate.

Some Republicans actually believe the biennial cliché that the present election is the most important of their lifetime — and that the future of the republic depends on a new GOP majority that can rein in President Obama. So a White House hopeful seen as doing anything but advancing the cause would invite opprobrium.