Republican Presidential candidate Rep. Michele Bachmann, R-Minn. meets with patrons at the Nodaway Diner during a campaign stop, Wednesday, Dec. 28, 2011, in Greenfield, Iowa. (Evan Vucci/AP)

DES MOINES — Despite her cratering poll numbers and the defection of her Iowa chairman, Rep. Michele Bachmann (Minn.) vowed Thursday to forge ahead with her campaign for the GOP nomination.

Bachmann, who is set to finish a week-long bus tour of all 99 Iowa counties today, said the reality that she is seeing on the ground five days before the caucuses is exactly the opposite of what the polls are showing.

Yet there was surely some unintentional irony in her declaration that “what we have seen is an outpouring of momentum . . . unlike anything we have ever seen.”

In August, Bachmann won the much-ballyhooed GOP straw poll in Ames. But her candidacy has since been left by the wayside, as a succession of other Republican contenders have moved to center stage as the leading alternative to presumed front-runner Mitt Romney, the former governor of Massachusetts.

Now it appears the candidate who is moving forward is Rep. Ron Paul (Tex.). On Wednesday night, the Bachmann campaign was stunned when its Iowa chairman, state Sen. Kent Sorenson, ditched her for Paul.

Speaking outside a radio studio here, Bachmann insisted that she is seeing “literally hundreds and thousand of people flipping” the other way, from supporting Paul's campaign to backing hers. She also repeated her contention that Sorenson had been offered money by the Paul campaign to make the switch — an assertion that her own Iowa political director, Wes Enos, disputes.

Bachmann also said once again that Paul would be a dangerous choice for the Republicans, given his isolationist foreign policy views and his stances on social issues, which include support for legalizing drugs.

And in an apparent reference to Romney, she added that the party cannot afford to pick a “frugal socialist” — a phrase that nearly echoed Sorenson’s explanation the night before of why he had switched his loyalties to Paul, whom he considers a more viable alternative to the former Massachusetts governor.