New Cain Web ad jokes about 'smoking tractors'

The release of the ad comes as the campaign tries to shift the narrative away from a second week of questions about alleged incidents of sexual harassment when Cain served as president of the National Restaurant Association.

But that effort seems unlikely to succeed after Sharon Bialek, a former employee of the association's education foundation, called a press conference Monday afternoon and accused Cain of groping her and making unwelcome sexual advances after a dinner in 1997. Cain denied the allegations.

That news has overshadowed Cain's campaign successes, including an endorsement by Dean Kleckner, an Iowa farmer who served as president of the American Farm Bureau from 1986 to 2000.

Kleckner's endorsement is featured in the ad, along with other Iowa farmers mocking EPA regulations that would restrict dust emissions.

“Seventy percent of Iowa caucus voters come from small towns and farms. We want Iowans and farmers across America to know that Herman Cain realizes farming is a business and excessive government regulation will drive farmers out of business just like it does for manufacturers,” said Steve Grubbs, Cain's Iowa chairman, in a statement.