President Trump’s tough criticism of Special Counsel Robert Mueller signals a renewed effort to challenge his investigators’ credibility over their track record of pro-Democratic political donations and other associations.

There is no shortage of examples to fuel the president’s case.

Of the 15 attorneys currently on staff for Mueller, at least seven have donated to Democratic candidates and campaigns, including Trump’s 2016 rival Hillary Clinton. The rest have not made political donations, according to federal records; and none of the attorneys on Mueller’s roster donated money to Trump. 

“This is just a witch hunt—it’s all a hoax,” White House Counselor Kellyanne Conway told “Fox & Friends” last week after Trump criticized Mueller in a New York Times interview. “People should know what folks’ past motivations, and their political motivations are—these weren’t minor donations, these were significant donations by members of that team.”