Senate Minority Leader Chuck Schumer (D-NY) defended the special counsel now in charge of the investigation into Russian meddling in the 2016 election on Monday, calling attacks by some powerful conservative personalities against him “a shameful, shameful ploy.”

Schumer, speaking on the Senate floor, said attacks on special counsel Robert Mueller, the former FBI director appointed by Deputy Attorney General Rod Rosenstein in mid-May to lead the investigation, “won’t do a thing to deter Director Mueller from finding out the truth.”

Over the weekend and on Monday, conservative heavyweights, including former House Speaker Newt Gingrich, began attacking Mueller’s impartiality. Ann Coulter, the conservative provocateur, said fired FBI Director James Comey’s acknowledgements to Trump that he wasn’t under investigation had made Mueller’s position unnecessary. Coulter and Gingrich both welcomed Mueller’s appointment at the time.

“Already, former Speaker Gingrich and others have said negative things about Mueller just weeks after praising his selection,” Schumer said. “They know that Mr. Mueller is the man now responsible for following up on Mr. Comey’s testimony, so the hard right is trying to discredit him in advance. They know they can’t debate the facts or the issues or defend the actions of the White House on the merits, so what do they do? They attack the referee and try to besmirch the reputation of someone like Mr. Mueller.”

Schumer added later: “The right must be afraid of what Mr. Mueller’s going to find. I would ask Speaker Gingrich a question: Is he afraid of what Mr. Mueller is going to find out? Is that why he is attacking his reputation? The baseless attacks on former Director Mueller ring hollow.”