“I think we’re in impeachment territory.”

Those were not the words of a left-wing political blogger with high hopes, nor a hyperactive Twitter maven spouting conspiracy theories. They came from David Gergen, the typically moderate, mild-mannered CNN analyst and former aide to four presidents, both Republican and Democrat.

Gergen appeared on CNN Tuesday night to discuss the controversies that have overwhelmed the Trump administration in the past week.

At the top of the list were reports that President Trump had asked then-FBI Director James B. Comey to drop an investigation into Michael Flynn, the former national security adviser. The revelation has fueled claims that Trump might have obstructed justice, which in the past has been treated as an impeachable offense.

If true, it could mean devastating consequences for the president, said Gergen, who served under Presidents Richard Nixon and Bill Clinton, both of whom faced the impeachment process.

“I was in the Nixon administration, as you know, and I thought after watching the Clinton impeachment I’d never see another one,” Gergen told host Anderson Cooper. “But I think we’re in impeachment territory now for the first time.”

Cooper asked: “Really?”

“I think that obstruction of justice was the number one charge against Nixon that brought him down,” Gergen responded. “Obstruction of justice was the number one charge against Bill Clinton, which led to his indictment in the House.”

In controversy after controversy, Republican lawmakers have defended President Trump's actions. But with his disclosure of highly classified information to Russian diplomats, they've floundered to explain the decision. (Jenny Starrs/The Washington Post)

The New York Times first, then The Washington Post and other outlets have reported that Trump had asked Comey in a February meeting not to pursue the Flynn probe and instead go after journalists in leak cases. Comey shared his notes from the conversation with aides, who in turn described the notes to reporters. Legal analysts told The Washington Post Tuesday that a criminal obstruction-of-justice case is possible but would likely require more evidence.

The news came within a week of Trump’s dismissal of Comey and a day after reports that Trump had shared classified information with Russia.

The White House denied the version of the conversation described by Comey’s aides, telling The Post “the president has never asked Mr. Comey or anyone else to end an investigation.” Trump has separately defended his firing of Comey and his sharing of information with Russian officials.

On CNN, Gergen said that “from a lay point of view” it appeared Trump was trying to impede the FBI’s investigation.

“He was using his power to do that, and when James Comey didn’t go along with him, when he wasn’t his boy, he fired him, which I think is also relevant to the question of what he was trying to do,” Gergen said. “So from my point of view this is of enormous consequence for his presidency.”

“I think if you look at the three bombshells we’ve had,” Gergen added, “what we see is a presidency that’s starting to come apart.”

Gergen wasn’t the only moderate voice to suggest Tuesday that a plausible case for Trump’s removal was emerging.

Ross Douthat, a conservative columnist for the New York Times and longtime critic of Trump, wrote that while Trump may not be guilty of the “high crimes and misdemeanors” necessary for impeachment, he had shown himself incapable of governing the country. A more appropriate solution, Douthat argued, was to remove Trump under the 25th Amendment, which allows the president’s cabinet to deem him “unable to discharge the powers and duties of his office.”

“It is not squishy New York Times conservatives who regard the president as a child, an intellectual void, a hopeless case, a threat to national security,” Douthat wrote. “It is people who are self-selected loyalists, who supported him in the campaign, who daily go to work for him.”

The 25th Amendment, ratified in 1967 in the wake of the assassination of John F. Kennedy, sets out both a plan of succession for the presidency and a complicated and daunting means of removing a president deemed incapacitated.

The relevant Section 4 reads as follows:

Whenever the Vice President and a majority of either the principal officers of the executive departments or of such other body as Congress may by law provide, transmit to the President pro tempore of the Senate and the Speaker of the House of Representatives their written declaration that the President is unable to discharge the powers and duties of his office, the Vice President shall immediately assume the powers and duties of the office as Acting President. Thereafter, when the President transmits to the President pro tempore of the Senate and the Speaker of the House of Representatives his written declaration that no inability exists, he shall resume the powers and duties of his office unless the Vice President and a majority of either the principal officers of the executive department or of such other body as Congress may by law provide, transmit within four days to the President pro tempore of the Senate and the Speaker of the House of Representatives their written declaration that the President is unable to discharge the powers and duties of his office. Thereupon Congress shall decide the issue, assembling within forty-eight hours for that purpose if not in session. If the Congress, within twenty-one days after receipt of the latter written declaration, or, if Congress is not in session, within twenty-one days after Congress is required to assemble, determines by two-thirds vote of both Houses that the President is unable to discharge the powers and duties of his office, the Vice President shall continue to discharge the same as Acting President; otherwise, the President shall resume the powers and duties of his office.

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