It remains unlikely that Donald Trump will make like Richard Nixon and resign to avoid impeachment — especially given that he's been impeached already, was acquitted in the Senate, and only has nine days left in office. But House Speaker Nancy Pelosi restated the case that this is what should happen in an interview with Lesley Stahl on 60 Minutes on Sunday.

Pelosi penned a letter on Friday urging Republicans in Congress to press the president into resigning, in order to avoid the political tension and further embarrassment of a second impeachment proceeding. On Monday, the House introduced a single article of impeachment charging the president with abuse of power, due to "inciting an insurrection" last Wednesday. And pressure remains high on Vice President Mike Pence to invoke the 25th Amendment, although he appeared to indicate last week that he was not open to the idea.

When Stahl, in the interview with Pelosi, suggested that the 25th Amendment was "off the table" now, Pelosi replied, "Nothing is off the table."

But she seemed to still say that a resignation was the best and quickest course of action.

"I remember when Republicans in the Senate went to see Richard Nixon [in August 1974] and said, 'It's over,'" Pelosi said. "That's what has to happen now."

Pelosi said she remained concerned that the president might try something reckless, militarily, in his final days in office, and she talked about seeking advice from General Mark Milley, the Chairman of the Joint Chiefs of Staff, about whether there were any protections against this.

Pelosi says that she and Schumer called Pence to discuss invoking the 25th Amendment, and they were kept on hold for 20 minutes before hanging up.

"We're still waiting for him to return the call," she said.

There was also some discussion in the interview about Pelosi's age (80) and that of senior leadership (also around 80) in her caucus, and Stahl asked why she had not brought younger people into leadership roles.

"We have," Pelosi insisted. And when asked why Rep. Alexandria Ocasio-Cortez thinks they haven't, Pelosi just said, "You'll have to ask her," and referred to the many other members of the caucus who are very effective but whom the press pays little attention to.

Related: Pelosi Invokes Nixon, Presses Republicans to Secure Trump's Resignation