Instead of changing plans and skipping Iowa, as John McCain did on the Republican side, Mr. Bradley slogged on.

Mr. McCain skipped Iowa and is concentrating on New Hampshire, where he leads Mr. Bush in some surveys.

Mr Huntsman, who has staked his entire campaign on New Hampshire after skipping Iowa, has steadily risen to third place with 11 per cent.

Aides to Senator Joseph I. Lieberman of Connecticut, who also skipped Iowa, said he drew inspiration from Mr. Edwards's strong performance.

It remains an open question, however, how large a price in news media attention he will have paid for skipping Iowa and New Hampshire.

Waiting for them there were General Clark and Mr. Lieberman, both of whom decided to skip Iowa, where they expected to lose.

Jon Huntsman, Mr Obama's former ambassador to China, finished third with 17, after skipping Iowa and staking his entire campaign on the state.

A Paul victory would have given future Republican candidates an automatic pass to skip Iowa.

General Clark, who entered the race late and made a calculated decision to skip Iowa, may live to regret his choice.

Still burned by this experience, Mr Romney's original intention for 2012 was to skip Iowa, perhaps thereby rendering the contest relatively meaningless.