Obama Campaigns in Wisconsin Against Walker

A rare election appearance

President Barack Obama is kicking off a weeklong, six-state campaign spree with a visit to Wisconsin.

Obama will attend a rally at a Milwaukee high school Tuesday for Mary Burke, the Democrat trying to oust Republican Gov. Scott Walker. Defeating Walker, a potential 2016 presidential contender, would be a major coup for Democrats.

The president has been a rare sight on the campaign trail this year, where his low approval ratings make him a potential liability for his party. But in states like Wisconsin, Democrats are hoping high turnout among die-hard Obama supporters will put them over the top in hard-fought races for governor.