Herman Cain’s popularity sinks in new Iowa poll

Herman Cain's popularity has dramatically plummeted in Iowa, amid past allegations of sexual harassment and a claim that he cheated on his wife with an Atlanta woman.

A new Des Moines Register poll of likely Iowa caucus-goers finds Cain with just 8 percent support ahead of the state's Jan. 3 vote—a 15-point drop since late October.

Cain was the frontrunner in several recent Iowa polls, but according to preliminary results of the Register poll, which will be released in full on Saturday night, voters are increasingly having doubts about Cain's candidacy.

Twenty-seven percent of likely caucus-goers believe Cain is the "least knowledgeable" in the 2012 Republican presidential field—topping all of his GOP rivals in that category.

Cain's candidacy also appears to be taking a direct hit from a claim made this week by Atlanta businesswoman Ginger White that she had a 13-year extramarital affair with the candidate.

According to the Register, 22 percent of voters said Cain was the candidate they most wanted to see in person during polling on Sunday and Monday of this week. But that number dropped to just 8 percent during polling on Tuesday and Wednesday—after White went public with her claims of an affair.

On Thursday, Cain told the New Hampshire Union Leader he had given White financial assistance over the years--though he declined to say how much. Still, he admitted he had not told his wife, Gloria, about his dealings with White.

Eleven percent of likely Iowa caucus-goers now say Cain is the candidate they like the least—an 8 point increase since October.

Other popular Yahoo! News stories:

Want more of our best political stories? Visit The Ticket or connect with us on Facebook and follow us on Twitter.