President Donald Trump speaks during an event in the Rose Garden at the White House to declare a national emergency in order to build a wall along the southern border, Feb. 15, 2019, in Washington.
President Donald Trump speaks during an event in the Rose Garden at the White House to declare a national emergency in order to build a wall along the southern border, Feb. 15, 2019, in Washington.

U.S. President Donald Trump suggested Monday that key law enforcement officials engaged in "treasonous" activity when they considered invoking a constitutional amendment in 2017 to remove him from office while opening an obstruction of justice investigation against him.

Trump, from his oceanfront Mar-a-Lago estate in Florida, lashed out at former acting Federal Bureau of Investigation director Andrew McCabe, who told the CBS News show 60 Minutes Sunday night that he and Deputy Attorney General Rod Rosenstein discussed employing the 25th Amendment to the Constitution allowing a vice president and a majority of the 15 Cabinet members to declare a president incapable of handling the duties of the presidency, making the vice president the acting president.

McCabe said a "crime may have been committed" when Trump fired then FBI chief James Comey in May 2017 at the time Comey was heading the agency's investigation into Trump's campaign ties to Russia during the 2016 U.S. presidential election. Days later, Trump said he was thinking of "this Russia thing" when he decided to oust Comey.

McCabe, himself later fired after 21 years at the FBI, said, "And the idea is, if the president committed obstruction of justice, fired the director of the FBI 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?"

McCabe said Rosenstein, who is soon leaving the Justice Department, was "absolutely" onboard with the obstruction and counterintelligence investigations of Trump. Nothing came of the discussions about invoking the constitutional amendment.

Days after Comey's firing, Rosenstein named Robert Mueller, himself a former FBI director, as special counsel to take over the Russia investigation. Rosenstein had assumed control of the Russia investigation because then-Attorney General Jeff Sessions had removed himself from oversight because of his own discussions during the election campaign with Sergey Kislyak, Russia's former ambassador to the U.S. Sessions's recusal from oversight of the probe eventually led Trump to fire him last year.

"Wow, so many lies by now disgraced acting FBI Director Andrew McCabe," Trump said on Twitter. "He was fired for lying, and now his story gets even more deranged. He and Rod Rosenstein, who was hired by Jeff Sessions (another beauty), look like they were planning a very illegal act, and got caught." 

?Trump added, "There is a lot of explaining to do to the millions of people who had just elected a president who they really like and who has done a great job for them with the Military, Vets, Economy and so much more. This was the illegal and treasonous "insurance policy" in full action!" 

?McCabe said that Trump's request early in his administration to Comey that he drop the FBI's investigation of former national security adviser Michael Flynn and his discussions with Kislyak also contributed to the FBI's suspicion of Trump's actions.

"Put together, these circumstances were articulable facts that indicated that a crime may have been committed," McCabe said. "The president may have been engaged in obstruction of justice in the firing of Jim Comey."

McCabe said Rosenstein at one point offered to wear a wire to a White House meeting with Trump to document their conversations. McCabe said Rosenstein's comment was made in a conversation about Comey's firing, but the Justice Department said last year the comment was sarcastic in nature, not serious.

McCabe was fired last year by Sessions, a day short of gaining full retirement benefits. The Justice Department said he was dismissed because he misled investigators during an internal probe of a disclosure about an investigation to the Wall Street Journal, a claim McCabe rejected.

"I believe I was fired because I opened a case against the president of the United States," he said.

Republican Sen. Lindsey Graham gestures as he spea
FILE - Republican Sen. Lindsey Graham.

Sen. Lindsey Graham, a South Carolina Republican who is one of Trump's staunchest supporters, said Sunday he plans to open an investigation into McCabe's claims there was a discussion of trying to remove Trump from office by invoking the constitutional amendment. 

"The deputy attorney general denies it," Graham said. "We will have a hearing about who's telling the truth, what actually happened."

Graham added, "We're a democracy. People enforce the law -- can't take it into their own hands. And was this an attempted bureaucratic coup? I don't know."

Mueller is 21 months into his investigation into Russian meddling in the 2016 election, the Trump campaign links to Russia and whether Trump, as president, obstructed justice by trying to thwart the probe.

He has won convictions for various offenses against five key officials in Trump's orbit, including Flynn, former campaign manager Paul Manafort and his deputy, Rick Gates, former foreign affairs adviser George Papadopoulos and former Trump personal attorney Michael Cohen, while indicting longtime Trump adviser Roger Stone. 

Trump has repeatedly denied any collusion with Russia during the campaign or that he obstructed justice.