President Donald Trump’s legal team became significantly more cohesive on Wednesday with the addition of Emmet Flood, a veteran white collar defense attorney. It also became more aggressive, which could prove tricky for special counsel Bob Mueller.

A longtime Washington lawyer who’s known Flood for quite some time and who spoke anonymously because of client sensitivities said there’s no chance Flood will let the president sit for an interview with Mueller.

“Mueller finally has somebody who’s his match,” that person said. “You’ve got a fair fight now.”

The person also said White House counsel Don McGahn played a significant role in bringing Flood onto the president’s legal team—pushing for him to be offered Ty Cobb’s job and working to convince him to take the position. McGahn and Cobb reportedly had frequent clashes about how to handle the president’s legal woes, and Cobb was overheard complaining about McGahn at the BLT Steak restaurant a few blocks from the White House. With Flood, the president’s lawyers are likely to be more unified in an aggressive posture toward Mueller.

“He comes across like a Columbo-type—unassuming, but the intellect is gargantuan,” the person added.

Flood will step into live negotiations between the president’s lawyers and Mueller’s team. The Washington Post reported yesterday that Mueller’s lawyers have floated the possibility of subpoenaing the president. Such a move would likely lead to a protracted court battle.

Flood’s roots are in top legal circles, and he has extensive experience in high-profile political investigations. He clerked for Justice Antonin Scalia and was a junior lawyer on the team that helped then-President Bill Clinton navigate impeachment proceedings. He went on to the White House Counsel’s office under George W. Bush where he was known for the work he did on the scandal related to the firings of U.S. attorneys. Members of Congress lambasted that White House for not letting senior staffers Harriet Miers and Josh Bolten testify, and ultimately held the pair in contempt. But the Justice Department declined to prosecute the pair for stiff-arming the Hill and Flood was a central White House lawyer managing that crisis, according to a longtime Washington attorney who knows him.

“I’m frankly surprised that he’s willing to do it,” that attorney said of Flood’s decision to join the Trump White House. “He’s a patriot for stepping up.”

It was during the transition from the Bush presidency to Obama when Flood met Norm Eisen, a senior fellow in governance studies at the Brookings Institution, who served as Obama’s special counsel at the time.

“He’s one of the greats in defending scandals involving government officials. Maybe the best, in my generation,” Eisen said of Flood.“These scandals run hot, and he has the gift of cooling them down and slowing them down. It is like the way Neo slows down time in the Matrix to dodge bullets.”

David Rivkin, a former Justice Department and White House official in the Reagan and George H. W. Bush administrations, also said he expects Flood to be more combative than Cobb.

“It’s a definite step up from Ty Cobb,” Rivkin told The Daily Beast. “He’s not a constitutional lawyer, but he is first-rate.”

—with additional reporting by Sam Stein