The move comes after House Speaker Nancy Pelosi said Thursday that Trump was in an "altered state," but said Friday the measure wouldn't apply to him.
"This is not about President Trump. He will face the judgment of the voters. But he shows the need for us to create a process for future presidents," Pelosi told reporters at Capitol Hill news conference as she introduced the bill.
"This legislation applies to future presidents, but we are reminded of the necessity of action by the health of the current president," she added. "It’s not about any of us making a judgment about the president’s well-being."
When pressed by reporters if she thinks it's time to invoke the 25th Amendment concerning Trump, Pelosi responded: "That's not for us to decide."
The measure would create an expert panel - with members appointed by Democratic and Republican leaders of the House and Senate - to conduct a medical exam at the direction of Congress to “determine whether the President is mentally or physically unable to discharge the powers and duties of the office," according to the text of a version of the proposal introduced in 2017 by Rep. Jamie Raskin of Maryland.
Raskin, a former constitutional law professor and member of the House Judiciary Committee, said the panel would include doctors as well as former presidents and Cabinet secretaries, who would each serve four-year terms.
“The population is getting older, politicians are getting older,” he said in an interview earlier this week. “It's not hard to think that there will be future situations where the president's physical and mental state may create issues for us. So, we just need to make sure that we have a structure and a process in place to address it.”
Pelosi has repeatedly expressed concerns in public and private this week about President Trump’s health amid his treatment for COVID-19.
Trump, at the direction of his doctors, has been taking dexamethasone, a steroid used to reduce lung inflammation in COVID patients, that can, in some cases, prompt psychiatric side effects, including mood swings, rage and psychosis.
“The president is, shall we say, in an altered state right now,” Pelosi said Thursday during an interview with Bloomberg TV. “I don’t know how to answer for that behavior.”
She continued, "There are those who say when you are on steroids or have COVID-19, there may be some impairment of judgment.”
Dr. Sean Conley, Trump's White House physician, who has provided little information about the president's condition and repeatedly contradicted himself in press conferences over the weekend, claimed to reporters on Monday that Trump has not displayed any neurological symptoms from the coronavirus, or side effects from his treatment.
Republicans accused Pelosi of trying to undermine the president after she alluded to the new proposal in her weekly news conference. Trump responded swiftly via Twitter.
“Crazy Nancy is the one who should be under observation. They don’t call her Crazy for nothing!” the president said.
Senate Majority Leader Mitch McConnell called the new proposal "absurd."
"That’s absurd. Absolutely absurd. Right here, in this last three weeks before the election, I think those kinds of wild comments should be largely discounted," McConnell said on Friday during an event in Kentucky.
Pelosi, despite her misgivings about Trump, has not called for invoking the 25th Amendment against him or having the proposed fitness review measure apply to him.
“I don't say that would work for this president but I do think, well, for this presidency, you know, three and a half months, but we can establish it for the future so there's much more clarity and a backstop,” she said Tuesday night at a livestream event hosted by the 92nd Street Y in New York City.
Ratified in 1967 after the assassination of President John F. Kennedy, the 25th Amendment outlines procedures for a transfer of presidential power to the vice president in the cases of death, incapacitation, removal or resignation.
The amendment says the determination of whether a president can discharge their duties would be determined by the vice president and a majority of Cabinet secretaries or “such other body as Congress may by law provide,” which Raskin said his proposal is designed to establish.
The amendment states: “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.”
“Congress has not yet set up such a body but I think that we should,” Raskin told ABC News. “I wish it had been done after the 25th Amendment was adopted in 1967.”