MADISON, Wis. -

The race for Wisconsin governor is coming down to credibility, and Democratic candidate Tom Barrett is slamming Republican candidate Scott Walker on what he says are mixed messages.

In his campaign's first outright negative ad, Barrett calls Walker a flip-flopper.

"Scott Walker, he'll say anything to try and get elected," the ad says. "It took Walker less than 24 hours to flip-flop on the Arizona immigration law."

WISC-TV found this claim is true.

Much of the discussion on this issue took place on Walker's Facebook page, where he first posted on May 14 that he thought immigration was a federal issue and not for states to police. That was also reported by the Associated Press. Then 133 angry Facebook comments and 24 hours later, Walker's campaign posted a statement saying he'd spoken to the sponsor of the Arizona law and was now assured that the law meets the standards of states' rights, WISC-TV reported.

"Walker supported the smoking ban, but now he's flipped and wants to repeal it," the ad says.

WISC-TV found this misleading. Walker never supported the ban, but there is a question over whether he'd repeal it.

Walker first told a reporter one day after it went into effect that it was too early to seek exemptions to the law. But just days later, after Republican candidate Mark Neumann said he'd repeal the ban upon taking office, Walker also moved to that position, WISC-TV reported.

"Walker says he's for lower taxes, but Milwaukee County spending has gone up by $349 million," the ad says.

WISC-TV found this misleading. On taxes, Walker has proposed freezing the property tax levy at the prior year's level every year he has been in office as Milwaukee County executive. The Milwaukee County Board has overridden him every year.

Walker's budgets have gone up by $349 million, which includes money borrowed to spend and is similar to the amount spending went up in the city of Milwaukee under Barrett as well, WISC-TV reported.

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