Rep. Jamie Raskin (D-Md.), here at the Peace Ball on the night before Donald Trump’s inauguration, has authored a bill that would invoke a never-before-used part of the 25th Amendment to determine whether the president is capable of doing his job. (Sarah L. Voisin/The Washington Post)

In the nearly four months since Donald Trump took office, many Democrats have questioned his ability to run the country. But only Rep. Jamie B. Raskin has authored legislation to address those concerns.

The Maryland Democrat’s bill, called the Oversight Commission on Presidential Capacity Act, would invoke a never-before-used part of the 25th Amendment to determine whether the president is capable of doing his job.

Raskin, a constitutional law professor, said he started thinking about the bill as soon as he was elected to his first term in November. He said the issue has become increasingly relevant as constituents in his liberal Montgomery County district clamor for action in the Trump administration’s bumpy first months.

“This is a president who has insisted that Ted Cruz’s father was involved in the assassination of John F. Kennedy and that Barack Obama was born in Indonesia, and he has uttered blatant lies and never retracted them,” Raskin said in an interview Friday. “And that is a sign of a serious mental disturbance.”

White House spokesman Michael Short declined to comment on Raskin’s bill, saying in an email that he was “not going to dignify this with an official response.”

Raskin filed the bill in early April but alerted reporters to it Friday, hours after President Trump, in a tweet, implied to fired former FBI director James B. Comey that he had “tapes” of their private conversations.

“This is a president who seems increasingly at odds with everyone and everything around him,” said Raskin, who skipped Trump’s inauguration.

In the GOP-controlled House and Senate, the bill has little chance of passing or getting a hearing, but Raskin said he filed the bill to put a framework in place in case Trump’s party turns on him.

The bill has 20 Democratic co-sponsors, including Rep. Anthony G. Brown (Md.) and the District’s nonvoting delegate, Eleanor Holmes Norton.

Rep. Andy Harris, the only Republican representing Maryland in Congress, called the bill a cheap shot at Trump.

“To properly evaluate someone’s mental and physical health requires years of schooling, and it is an insult to the entire medical profession to assume that unqualified, agenda-pushing, partisan politicians would be able to make such a critical professional judgment,” said Harris, an anesthesiologist who specializes in obstetrics. “This legislation is a thinly veiled attempt by Democrats to undermine a legislative agenda they disagree with.”

Parts of the 25th Amendment that provide for temporary transfer of power from the president to the vice president have been invoked when Presidents Ronald Reagan and George W. Bush underwent surgeries.

But Raskin’s bill would activate Section 4 of the 25th Amendment to create an independent, nonpartisan commission to determine whether the president is physically or psychologically unfit for office.

Once created, the 11-member commission would be permanent. But it would not have roving power to diagnose the president. Congress would have to pass a resolution empowering the commission to examine the president and his conduct and report its findings. If the president were found to be incapacitated, the vice president would immediately become acting president.

Under Raskin’s bill, the speaker of the House, House minority leader, Senate majority leader and Senate minority leader would each select one physician and one psychiatrist to serve on the commission. The Republican and Democratic parties would each select a retired statesperson. And those 10 appointees would choose an 11th member to lead the commission.

“It certainly doesn’t feel like the ship is on an even course right now,” Raskin said. “We are careening all over the place.”