Texas Rep. Ron Paul predicted Sunday that he would finish in first or second place when Iowa Republicans hold caucuses Tuesday night.

"I may come in first. I may come in second," Paul said on CNN's "State of the Union." "I doubt if I'll come in third or fourth."

A Des Moines Register poll released Saturday night put the Texas congressman in second place, with 22 percent, right on the heels of former Massachusetts Gov. Mitt Romney, who tops the field heading into Tuesday night's vote as the top pick of 24 percent of likely caucus-goers.

But that survey also showed former Pennsylvania Sen. Rick Santorum, who has spent much of the year at the back of the pack, gaining ground, as the favored choice of 15 percent of people expected to cast ballots on Tuesday night.

By just considering the final two days of the four-day poll, Santorum edges Paul, 21 percent to 18 percent, news that may upset the Texas congressman's New Year's Day prediction.

Paul brushed aside the Santorum surge as the latest example of an erratic electorate that has rushed from one flavor-of-the-month candidate to the next, starting with Rep. Michele Bachmann (R-Minn.) and most recently elevating former House Speaker Newt Gingrich as the expected front-runner in Iowa and beyond.

Gingrich dropped to 12 percent in the latest Des Moines Register poll after leading the field at 25 percent in an earlier survey taken at the end of November.

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