One of the high prophets of “campaign finance reform,” Russ Feingold, is singing a new tune these days. Juliegrace Brufke reports for the Daily Caller.

Former Sen. Russ Feingold failed to denounce six groups associated with dark money – which he has strongly criticized in the past – for running campaign ads against his opponent, Wisconsin Republican Sen. Ron Johnson.

The Environmental Defense Action Fund, VoteVets.Org, NARAL Pro-Choice, Planned Parenthood, American Bridge and the League of Conservation Voters spent more than $2 million in attack ads against the incumbent by the end of 2015. Feingold is currently running against Johnson in a bid to return to the Senate.

Feingold even held a rally with the League of Conservation Voters – a group dubbed “one of the nation’s strongest ‘dark money’ forces” in politics by The Center of Public Integrity – in late May.

It appears the former senator has completely changed his tune on third-party groups. Back in 1998, he told the National Democratic Senatorial Committee to “get the hell out of my state” after offering to dump $425,000 into an ad campaign for him.

“He used to be against these groups and now he’s relying on them,” a source close to the Johnson camp told The Daily Caller News Foundation. “This from the guy who built his whole reputation on campaign finance reform and adamantly being opposed to these types of groups. Having their support is totally new for him in 2016.”