Among those Mr. Bannon plans to take on from that perch? The speaker of the House, Paul D. Ryan of Wisconsin, and Senator Mitch McConnell of Kentucky, the majority leader, two Republicans Mr. Bannon accused of âtrying to nullify the 2016 election.â
âThey do not want Donald Trumpâs populist, economic nationalist agenda to be implemented,â Mr. Bannon said. âItâs obvious as night follows day.â He cited as an example a request that Mr. McConnell once made of Mr. Trump to stop talking about âdraining the swamp.â
Mr. Bannon predicted deep division within the Republican Party over Mr. Trumpâs recent move to end the program that provided temporary relief from deportation for hundreds of thousands of young people in the United States illegally. The president set a March end date for the program and asked Congress to come up with a solution in the meantime, a task that Mr. Bannon said could split Republicans and cost them their House majority in the 2018 midterm elections.
âIf this goes all the way down to its logical conclusion, in February and March it will be a civil war inside the Republican Party,â he said.
When the interviewer, Charlie Rose, asked whether Mr. Bannonâs opposition to the immigration program was true to his Catholic faith, Mr. Bannon took aim at church leaders and claimed that they relied on illegal immigration to fill pews.
âThe bishops have been terrible about this,â he said. âYou know why? Because unable to really to come to grips with the problems in the church, they need illegal aliens. They need illegal aliens to fill the churches.â
Cardinal Timothy M. Dolan, the archbishop of New York, called Mr. Bannonâs comments âpreposterous and rather insulting.â
In the from his home in Washington, Mr. Bannon reacted defensively when asked whether his clout in the White House had diminished by the time he left.
âI had the same influence on the president I had on Day 1,â he said.
Mr. Bannon, who is often critical of those he sees as Washington careerists hostile to Mr. Trump, has become famous for his polemics that critics see as reflections of the presidentâs impulses.
âThe media image, I think, is pretty accurate,â he said. âIâm a street fighter. Thatâs what I am.â
Mr. Bannon also condemned top officials in the George W. Bush administration, referring to them as âidiotsâ friendly to what he termed Chinaâs anti-American economic agenda. He singled out Condoleezza Rice and Colin L. Powell, the former secretaries of state, and Brent Scowcroft, an adviser to both Mr. Bush and his father, as the figures most worthy of his scorn, criticizing them for Chinaâs 2001 entry into the World Trade Organization.
âTheyâve gotten us in this situation, and they question a good man like Donald Trump,â Mr. Bannon said. âI hold these people in contempt, total and complete contempt.â
He also called the special counsel investigation of possible links between the Trump campaign and Russian interference in the election a âwaste of time.â
âItâs a total and complete farce,â he said. âRussian collusion is a farce.â
Mr. Bannon seemed eager to pursue anyone who has crossed Mr. Trump. He claimed that he was âthe only guy that came out and tried to defendâ Mr. Trump after the racially tinged violence in Charlottesville, Va., last month, when Mr. Trump was widely condemned for statements that likened white supremacists to people protesting them.
âI was the only guy that said, âHeâs talking about something, taking it up to a higher level,ââ Mr. Bannon said in the â60 Minutesâ interview, echoing Mr. Trumpâs language in the days after the Charlottesville violence. âWhere does this end? Does it end â does it end in taking down the Washington Monument?â
Yet Mr. Bannon accused neo-Nazis of âgetting a free ride off Donald Trumpâ for their role in white supremacist rallies.
âThe left-wing media makes them up as some huge part of Donald Trumpâs coalition,â he said. âItâs a small group. Itâs a vicious group. They add no value. And all they do is show up.â
Mr. Bannon told Mr. Rose that he did not âneed the affirmation of the mainstream media.â
Neither does Mr. Trump, Mr. Bannon said.
âI donât think he needs The Washington Post, and The New York Times, and CBS News,â he said. âAnd I donât believe he thinks that theyâre looking out whatâs in his best interest, O.K.?â
Mr. Bannon also attacked Gary D. Cohn, Mr. Trumpâs top economic adviser, who publicly criticized the presidentâs comments about Charlottesville.
âIf you donât like what heâs doing and you donât agree with it, you have an obligation to resign,â Mr. Bannon told Mr. Rose. âYou can tell him, âHey, maybe you can do it a better way.â But if youâre going to break, then resign.â
Mr. Bannon acknowledged frequent schisms between competing factions among White House aides.
âI think there has been a divide in this administration from the beginning. Itâs quite obvious,â Mr. Bannon said. âThereâs one group of people that on the campaign that said: âAll you have to do is do what you said you were going to do in these major areas. Letâs punch out one thing after the other. Youâre going to keep your coalition together, and weâre going to add to it over time as youâre successful.â Thereâs another group that has said, âLetâs compromise, and letâs try to reach out to Democrats and letâs try to work on things that we can do together.ââ
When Mr. Rose asked whether John F. Kelly, the recently appointed White House chief of staff and retired Marine general, could ease the presidentâs outbursts on Twitter, Mr. Bannon predicted that Mr. Kelly would have a difficult time doing so, just as the former White House chief of staff, Reince Priebus, did.
âGeneral Kelly, I have the most tremendous respect for,â Mr. Bannon said. âHeâs not going to be able to control it either because itâs Donald Trump.â