President Joe Biden is preparing to endorse significant proposals to reform the Supreme Court and notified some members of Congress about his intentions last weekend, three sources familiar with the plans said Tuesday.

The proposals under serious consideration include legislation to establish term limits for justices and establishing an updated code of ethics that would be binding and enforceable, a source said. The policies, which haven't been finalized, may be rolled out in the coming weeks, which would be a new approach for a president who has long been skeptical of restructuring the Supreme Court.

A White House spokesperson declined to comment.

Biden told lawmakers in the Congressional Progressive Caucus during a virtual meeting Saturday that he had been consulting constitutional scholars on the matter for more than a month, according to a person familiar with the discussion.

"I'm going to need your help to and advice on how we should be doing what I'm going to be doing there. Want to make sure we have a closer working relationship, because we're in this together," Biden told the lawmakers, though he didn't get into specific policy substance, the source said.

The Washington Post first reported Biden's plans.

Two other sources told NBC News that Biden told the lawmakers he will come out for big reforms, without giving them details, but that members on the call understood him to be referring to term limits and ethics rules. The call took place Saturday before the assassination attempt on former President Donald Trump at a Pennsylvania rally.

"Look, it's not, it's not hyperbole to suggest Trump is literally an existential threat, an existential threat to the very constitution of democracy we, we say we care about. And I mean if this guy wins, he's not, and now, especially with that Supreme Court giving him the kind of breadth of — I don't need to get into the Supreme Court right now — anyway, but I need your help," Biden said, according to a source who provided this excerpt.

Changing the structure of the Supreme Court would require Congress to make a new law. That's extremely unlikely while Republicans control the House, as the party is pleased with the 6-3 conservative majority it has built on the high court.

But the proposals could become a useful messaging device for Biden on the campaign trail. And if Democrats sweep the election, they may have a fighting chance of passing. Democrats have rallied voters against the Supreme Court, citing unpopular rulings like the elimination of federal abortion rights and a spate of recent reports detailing apparent ethical lapses among some of the justices.

Last month, Senate Democrats sought to pass Supreme Court ethics legislation but ran into Republican opposition. In the House, Reps. Ro Khanna, D-Calif., and Don Beyer, D-Va., have introduced legislation that would impose 18-year term limits for future justices, ultimately creating vacancies to fill during every four-year presidential term and preventing retirements for partisan reasons.

Khanna praised Biden for warming up to the idea, noting that he first introduced term limits legislation in 2020.

"Since then, we have been advocating for the president to champion this reform," Khanna told NBC News on Tuesday. "It is a big step for him to now call for commonsense term limits for the court and a judicial code of ethics."