WASHINGTON — It’s been more than a year since any sort of war room has been run out of the basement of Stephen K. Bannon’s Capitol Hill townhouse. And it’s been even longer since Mr. Bannon, who was pushed out as White House chief strategist in August 2017, ran a war room for President Trump.

But everyday for the next two months — or “until the day after the acquittal of Donald J. Trump,” in Mr. Bannon’s words — a rogue, freelance messaging operation to fight impeachment is being broadcast there. The people involved in the radio show, all former Trump aides and supporters, say their intentions are clear: They want to nudge the White House, its allies and the president himself into taking a more focused and aggressive posture to undermine the inquiry currently underway in the House of Representatives.

On Wednesday, during the third episode of the show, which is called “War Room,” the hosts sat at a dining room table covered in a spaghetti salad of microphone wires, and dispensed an hour’s worth of unsolicited advice.

Stop calling the inquiry a “witch hunt” and a “deep state” conspiracy, they said by way of guidance to the president and his advisers, because it’s deluding too many Trump supporters into a sense of complacency.

Stop insisting that polls showing majority public support for the impeachment inquiry are “fake news” — because they aren’t.

Stop dismissing everyone who testifies about the Trump administration’s dealings with Ukraine as a radical unelected bureaucrat.

And stop letting Rudolph W. Giuliani, Mr. Trump’s personal lawyer, go on Laura Ingraham’s and Sean Hannity’s prime time Fox News programs to defend the president.

“We can’t do the Rudy thing anymore,” said Mr. Bannon, who in his days as a Trump adviser — and proud provocateur — pushed the nationalist ideology that the president adopted. “Too many Ukrainian names, too many moving pieces.”

Mostly nodding along in agreement were his co-hosts, Jason Miller, the former communications director of the Trump campaign in 2016, and Raheem Kassam, a former editor at Breitbart. Mr. Giuliani’s defense of the president — often a nonlinear timeline of events; a lengthy cast of characters involving the events in question in Ukraine; and a blanket insistence of “no quid pro quo” — is too confusing, they agreed.

“Here’s our fundamental problem: We don’t have an elevator pitch to easily describe this to the right,” Mr. Miller said. He likened the explanations from the White House and its surrogates to the way someone solves the game “Clue,” with its menagerie of possible culprits, weapons and crime scenes.

The show, which is airing on a half dozen stations in Virginia and Florida and streams on the website WarRoom.org, is a remarkably blunt attempt by former Trump aides to criticize and influence the work of current Trump administration officials. Even the show’s name is something of an affront to the White House — and to Mr. Trump himself. He has told aides that he does not want to create a war room, as crisis response operations are often nicknamed, because he is concerned that people would see it as an acknowledgment that he views the impeachment inquiry as legitimate.

Though many in the White House may be tempted to dismiss the show as a bootleg operation run by people cut off from Mr. Trump’s inner circle, Mr. Miller said in an interview that the president ultimately cares about one thing when it comes to managing a crisis of this magnitude: “Are there people defending me or not?”

Mr. Miller added that with the exception of a handful of Trump loyalists, “There is a serious lack of Trump allies jumping out there and defending the president.” Too few Republicans, he said, are questioning the process of the House Democrats’ impeachment inquiry, which he said was being run in a clandestine fashion from “Schiff’s secret Capitol basement bunker.” It was a reference to the secure hearing room in the Capitol where Representative Adam Schiff of California, the House Intelligence Committee chairman, is presiding over witness interviews.

The idea for the new program came to Mr. Bannon after he appeared last week on the radio show of John Fredericks, a conservative whose daily broadcast airs across Virginia. He was floored by the backlash he got when he stated what he said he assumed was accepted as fact among Republicans and Democrats alike: Mr. Trump is likely to be impeached.

CreditJustin T. Gellerson for The New York Times

“We’re like, ‘What the hell are you talking about?’” Mr. Fredericks said in an interview.

Many in Mr. Trump’s base, fed a heavy diet of talking White House talking points that House Democrats are attempting a “coup” without any evidence of wrongdoing, have come to believe that impeachment is a farce.

Mr. Fredericks faulted the White House. “That’s what the White House communications department pushed out for a month,” he said. “It’s fake news, deep state, witch hunt. It’s never going to amount to anything at all.”

While the hosts offered little praise for the White House messaging effort, their praise of House Speaker Nancy Pelosi was effusive.

In a broadcast earlier this week, Mr. Bannon warned Mr. Trump’s supporters not to be blinded by their animosity toward the speaker. “I don’t care if you hate Nancy Pelosi,” he said. “This is a master, and she is teaching a master class.”

“Tough as boot leather,” he added.

Mr. Miller said Wednesday that Ms. Pelosi is one of “the best communications directors on the planet,” who has been able to dominate news cycles by releasing key details from the closed-door testimony. That’s what Democrats did on Tuesday after William B. Taylor Jr., the top American diplomat in Ukraine, described how Mr. Trump held up $391 million in assistance for the purpose of forcing Ukraine to help Mr. Trump discredit his potential 2020 political rivals.

Ms. Pelosi, added Mr. Kassam, has figured out how to use the Congressional investigative process to the Democrats’ advantage. And Mr. Trump’s supporters can’t belittle that.

“There’s a very serious failure to take this whole process seriously from the Republican side,” he said.

As Mr. Trump railed about the saboteurs inside his administration on Wednesday, tweeting that the “Never Trumpers” like Mr. Taylor were out to get him, Mr. Bannon offered some feedback on the air. “All of these people,” he said, were “hired by Donald J. Trump or hired by people Donald J. Trump hired,” he said.