“We knew Trey Gowdy was abusing his power as chair of the Benghazi Committee to attack Hillary Clinton. What’s now clear is that he was doing so in order to help Marco Rubio run for president,” Rep. Steve Israel (D-N.Y.), former head of House Democrats’ campaign arm, said in a statement to POLITICO. “His actions in Congress and on the campaign trail are nothing more than to further his partisan political agenda.”

Gowdy, a former federal prosecutor, has maintained for months that he’s running a fair and impartial investigation that has nothing to do with politics. He abstained from some campaign events and fundraisers, and distanced himself from political comments made by fellow Republicans about his probe — largely out of concern that it could tarnish the Benghazi investigation’s integrity and give Democrats fodder to argue that it’s a partisan witch hunt.

Those efforts, he and his allies have acknowledged, didn’t protect him from accusations of partisanship and attacks from the left on his panel’s credibility. The complaints reached a crescendo in the weeks leading up to Clinton’s marathon appearance before his panel in October.

Now he appears to be casting aside that caution, plunging into the 2016 campaign.