The Democrats, in the US House of Representatives, said their legislation would activate a long-ignored provision of the 25th Amendment of the US Constitution, ratified in 1967, empowering Congress to create such a commission.
Democratic Representative Jamie Raskin, the bill's sponsor, said the 17-member commission would be made up of eight medical personnel, eight former executive-branch officials and a 17th member chosen by the group.
"What happens if a president, any president, ends up in a coma or on a ventilator and has made no provisions for the temporary transfer of power," Raskin said in urging that Congress pass his legislation next year.
House of Representatives Speaker Nancy Pelosi, a Democrat, was quick to say "this is not about President Trump," but about future presidents, which could include Trump if he wins a second four-year term in a Nov. 3 election.
Pelosi has raised experts' concerns that some of the drugs Trump took to battle his COVID-19 symptoms could cloud a person's judgment.
The 25th Amendment, sparked by the 1963 assassination of President John Kennedy, establishes the transfer of presidential power if a president or vice president dies or is incapacitated.
The Democratic legislation seeks to provide more clarity on the triggers for transferring power from the elected president or vice president to a temporary or permanent replacement.
House Minority Whip Steve Scalise, a Republican, accused Pelosi of trying to undo the results of the 2016 election, having failed to do so with the House impeachment of Trump that ended with a Senate acquittal.
"Here she is again ... trying to overturn the results of next month's election," Scalise told Fox News.