Republican Senator Lindsey Graham said he could subpoena Deputy Attorney General Rod Rosenstein and former FBI Deputy Director Andrew McCabe for a hearing to explore allegations they discussed whether President Donald Trump should be removed from office.

McCabe said in an interview to air on CBS’s “60 Minutes” Sunday that Rosenstein discussed with him in 2017 whether there were enough members of Trump’s cabinet who would support removing the president for being unfit under the constitution’s 25th Amendment. Rosenstein has denied that.

"The whole point of Congress existing is to provide oversight of the executive branch," Graham said on "Face the Nation" Sunday. "So through good reporting by '60 Minutes,' there's an allegation by the acting FBI director at the time that the deputy attorney general was basically trying to do an administrative coup, take the president down to the 25th Amendment process. The deputy attorney general denies it. So I promise your viewers the following, that we will have a hearing about who's telling the truth, what actually happened."

He added, "I'm going to do everything I can to get to the bottom of the Department of Justice FBI behavior toward President Trump and his campaign."

Graham called the idea of invoking the 25th Amendment "beyond stunning."

"I know he's selling a book, and we need to take with a grain of salt maybe what Mr. McCabe is telling us. But he went on national television and he made an accusation that floors me," said Graham.

Graham was then asked if he would be willing to subpoena McCabe and Rosenstein to testify before his committee.

"How can I not?" he answered.

He said the only way to find out the truth "is to call the people in under oath and find out through questioning."

An assertion that Rosenstein considered secretly recording Trump has been backed up in private testimony to Congress by two FBI lawyers. Both officials also told lawmakers that there was simultaneous talk in the spring of 2017, months after Trump’s inauguration, that two unidentified Cabinet officials were on board with the idea of invoking the 25th Amendment to remove Trump as president.

“It is alarming that there were apparently folks at the highest levels of our government considering whether or not our president is unfit to serve,” Democratic Senator Chris Coons of Delaware, a member of the Judiciary Committee, said on “Face the Nation.” Even so, he said, “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.”

Still, Coons said the matter deserves scrutiny, and “we should not be pursuing just one theory or one line of investigation here.”

McCabe was fired in March after internal FBI investigators found that he hadn’t been forthcoming about authorizing discussions with a reporter about a pending investigation. Trump has repeatedly excoriated McCabe on Twitter, and press secretary Sarah Huckabee Sanders said in a Feb. 14 statement that he “has no credibility.”

Asked on CNN’s “State of the Union” on Sunday whether McCabe should be charged -- as some Trump associates have -- with lying to investigators, Democratic Representative Adam Schiff said prosecutors must make an objective determination.

“He should be held to the same standard as anyone else that the Justice Department has looked at in this investigation or any other,” said Schiff of California, chairman of the House Intelligence Committee.