Former chief Trump strategist Steve Bannon is set to appear before a private conservative dinner in Manchester, New Hampshire, Thursday night, as he continues his war against the GOP establishment.

Bannon appeared at a Michigan GOP dinner Wednesday night, the day after Republicans were destroyed in New Jersey and Virginia races Tuesday night, to commemorate the one-year anniversary of the "high holy day of MAGA."

Bannon, who has declared war on the establishment GOP since he left the White House to return to his post as Breitbart News executive chairman, reminded attendees at the Macomb County GOP Unity Dinner in Detroit of Mr. Trump's victory one year ago Wednesday. On Wednesday, he called Election Day 2016, "the high holy day of MAGA," with "MAGA" standing for Mr. Trump's "make America great again" slogan.

Bannon laid out what he believes propelled Mr. Trump to the presidency — Mr. Trump's ability to be an agent of change, and a voice for the voiceless, he said.

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"The people don't care about locker room talk," Bannon said, referencing the explosive Access Hollywood tape, and saying people instead care about the "destruction" of the greatest country on earth. In the past, Bannon has said the tape was a "litmus test" for support for Mr. Trump.

"He understood the problems of the country," Bannon said. "He understood how to go to these massive rallies and connect with people like he was having a personal conversation."

Bannon did take a moment to reflect on the loss of Republicans in Virginia, where Democrat Ralph Northam handily beat Republican Ed Gillespie. Mr. Trump blamed Gillespie's loss on a failure to embrace his ideas, and Bannon spoke along similar lines.

Ed Gillespie worked hard but did not embrace me or what I stand for. Don’t forget, Republicans won 4 out of 4 House seats, and with the economy doing record numbers, we will continue to win, even bigger than before! — Donald J. Trump (@realDonaldTrump) November 8, 2017

Bannon said Gillespie is a "good man," but his failed campaign shows, "you can't fake the Trump agenda. You have to go all in."

Bannon decried "the swamp," as he describes Washington, D.C., railing against the political class of the nation's capital.

"We call it the swamp but it's not a cute thing to talk about," Bannon said. "It is a lethal, lethal system."

Bannon also blamed legislative failures in Washington on the "Republican establishment." Thus far, the GOP Congress has been unable to repeal and replace Obamacare, and a number of House Republicans are already saying they will not vote for the GOP tax bill.

"Most of the defeats are because the Republican establishment cannot execute on the plan," Bannon said, criticizing top Republicans like Senate Majority Leader Mitch McConnell.

The president's former top strategist said the road ahead to victory won't be simple, as 2018 looms ever nearer.

"We're going to have some dark days in front of us," Bannon said. "We're going to have some defeats in front of us."

Outside the building hosting the GOP dinner, dozens protested, as CBS Detroit reported.