WASHINGTON — Senator Lindsey Graham, the chairman of the Senate Judiciary Committee, vowed on Sunday to investigate whether the top officials at the Justice Department and the F.B.I. plotted an “attempted bureaucratic coup” to remove President Trump from office, and said he would subpoena the former F.B.I. director and the deputy attorney general if necessary.
Mr. Graham, Republican of South Carolina, was reacting to an interview in which the former F.B.I. deputy director, Andrew G. McCabe, confirmed an earlier New York Times report that the deputy attorney general, Rod J. Rosenstein, had suggested wearing a wire in meetings with Mr. Trump and that Justice Department officials had discussed recruiting cabinet members to invoke the 25th Amendment to remove Mr. Trump from office.
Mr. Rosenstein has disputed the account.
“I think everybody in the country needs to know if it happened,” Mr. Graham said on the CBS program “Face the Nation,” calling Mr. McCabe’s assertion “beyond stunning.” He added: “I’m going to do everything I can to get to the bottom of Department of Justice, F.B.I. behavior toward President Trump and his campaign.”
Asked by the program’s host, Margaret Brennan, if he would subpoena Mr. McCabe and Mr. Rosenstein to testify, Mr. Graham said, “How can I not if that’s what it takes?” He promised to have a hearing to find out “who’s telling the truth.”
A Democratic member of the Judiciary Committee, Senator Chris Coons of Delaware, agreed with Mr. Graham that Mr. McCabe’s remarks “deserve scrutiny.” But he took issue with Mr. Graham’s characterization of the situation.
“I don’t think that this frankly rises to the level of some deep state conspiracy or a serious attempt at what Senator Graham called an administrative coup,” said Mr. Coons, also speaking on “Face The Nation.” “I suspect that once this is fully discussed, it’ll be clearer that this was a brief or passing conversation that’s been taken out of context.”
Mr. McCabe made the explosive remarks in an interview with the CBS program “60 Minutes,” released in part on Thursday, in advance of its full airing Sunday evening. He said Justice Department officials became so alarmed by Mr. Trump’s decision in May 2017 to fire James B. Comey, the bureau’s director, that they discussed whether to recruit cabinet members to invoke the 25th Amendment, which outlines the succession plan should the president become incapacitated, resign or die in office.
In a second clip of the interview aired Sunday on “Face The Nation,” Mr. McCabe said he spoke to the president just after Mr. Comey was fired, and subsequently ordered the bureau’s team investigating Russia’s election interference to look into whether Mr. Trump had obstructed justice by firing Mr. Comey. The F.B.I. also began examining whether Mr. Trump had been working on behalf of Russia against American interests.
Mr. McCabe said that he and others were “concerned about a national security threat.”
He continued: “And the idea is, if the president committed obstruction of justice, fired the director of the F.B.I. to negatively impact or to shut down our investigation of Russia’s malign activity and possibly in support of his campaign, as a counterintelligence investigator you have to ask yourself, ‘Why would a president of the United States do that?’”
He added, “So all those same sorts of facts cause us to wonder, is there an inappropriate relationship, a connection between this president and our most fearsome enemy, the government of Russia?”
Mr. McCabe was fired by Jeff Sessions, the attorney general at the time, on the eve of his retirement in March 2018, after being accused of a lack of candor. The “60 Minutes” interview was part of a book tour to promote his memoir, “The Threat: How the F.B.I. Protects America in the Age of Terror and Trump,” which will be released this week.