Congressional Republicans reacted with mixed emotions on Friday after learning that White House chief strategist Steve Bannon had left the West Wing to return to the helm of Breitbart News, the hard-right website that has built its reputation on tormenting the GOP establishment.

"The Trump presidency that we fought for, and won, is over," Bannon declared in an interview with The Weekly Standard hours after the White House announced his departure. "We still have a huge movement, and we will make something of this Trump presidency. But that presidency is over."

Bannon was invited to join the administration after steering Trump's campaign through the final months of the presidential election, as the Republican nominee weathered the storm of the infamous "Access Hollywood" tape and faced a deluge of sexual assault allegations.

"As soon as he entered the White House, Bannon saw himself as the puppetmaster — the only one who could keep Trump bound to his agenda," a source close to the White House told the Washington Examiner, describing Bannon as "a ubiquitous presence."

His tactics weren't always popular, and often left him isolated in the West Wing. But some conservatives said they tolerated Bannon's worst flaws because they respected, and relied on, his effort to ensure Trump fulfilled promises he made to his base.

"We didn't interact much," one House GOP aide told the Washington Examiner. "But I know on several occasions he talked Trump down when the president wanted to retreat from certain issues."

Another source close to the White House said Bannon's departure means the "very liberal wing" of Trump advisers "is on the ascent and has a pretty big footprint between [Gary] Cohn, Dina Powell, Hope Hicks, Jared [Kushner], and Ivanka."

"Beyond the two Steves," the source said, referring to Bannon and White House senior policy adviser Stephen Miller, "you've got to question who is left to keep the president committed to his base."

At least two GOP aides described Bannon, along with Trump's ousted chief of staff Reince Priebus and White House legislative affairs director Marc Short, as a go-to contact on policy. For this reason, Freedom Caucus Chairman Mark Meadows, R-N.C., personally urged Trump last week to keep Bannon around, one of the aides said.

Other Republicans, who felt Bannon encouraged Trump's worst impulses, were quick to celebrate the dismissal of Bannon.

"First Scaramucci, now Bannon. Two great personnel decisions by [White House chief of staff] John Kelly," tweeted Sen. Pat Toomey, R-Pa., who was among several GOP senators to condemn Trump's erratic response to the violence in Charlottesville, Va., which Bannon later endorsed.

"The only time I ever interacted with Steve Bannon he was yelling at me, so I'm not going to shed a tear," Virginia Congressman Tom Garrett told reporters on Friday.

Garrett, another Freedom Caucus member, was one of several attendees of a White House meeting in March where Bannon ordered them to vote for the earliest version of the House GOP's bill to repeal and replace Obamacare.

"This is not a discussion. This is not a debate. You have no choice but to vote for this bill," Bannon had reportedly said at the time.