WASHINGTON — President Joe Biden on Monday proposed major changes to the US Supreme Court: an enforceable code of ethics, term limits for judges and a constitutional amendment that would limit judges’ recent rulings on presidential immunity.

There is almost no chance the proposal will pass a tightly divided Congress with Election Day looming, but the ideas could still spark conversation with public confidence in the court hitting an all-time low amid ethics revelations about some justices. It also comes against the backdrop of a controversial presidential election and growing Democratic outrage over recent rulings by the conservative majority court.

Here’s a look at how the ideas work, how they might work, and the possible stumbling blocks:

How would judges’ terms be limited?

Limiting the length of time justices serve on the nation’s highest court has broad support among Americans, polls show.

A July 2022 poll by The Associated Press-NORC Center for Public Affairs Research found that 67% of Americans support a proposal to set a specific number of years served by the judiciary instead of lifetime terms, including 82% of Democrats and 57% of Republicans.

Biden’s proposal would limit justices to 18-year terms, a system he says would make nominations more predictable, less arbitrary and reduce the chances that a single president could shape the court for generations to come.

There’s one big problem: the Constitution gives all federal judges life tenure, unless they resign, retire or are removed.

There are ideas about how to impose time limits without an amendment — but if such a law were passed and challenged in court, the judges could end up ruling on it and it’s unclear how they would go down, said Charles Geyh, a law professor at Indiana University and expert in legal ethics.

How would a code of ethics be enforced?

The Supreme Court did not have a formal ethics code until last year, when the justices adopted one in the face of persistent criticism over secret travel and gifts from wealthy benefactors to some justices, such as Clarence Thomas.

It still lacks a means of enforcement — something Biden says is “common sense.” Members of Congress, for example, generally cannot accept gifts worth more than $50.

Anyone can file complaints against other federal judges, who are subject to censure and reprimand. Justice Elena Kagan expressed support for adding an enforcement mechanism to the Supreme Court’s ethics code in a public appearance last week.

Making the Supreme Court’s code of ethics enforceable nevertheless raises difficult questions about how it can be enforced and by whom.

Lower courts say their disciplinary process isn’t intended to directly oversee their ethics code, enforcing the code is too broadly worded for violations to directly translate into discipline, Geyh said.

The ethics code is overseen by the Judicial Conference, which is chaired by Chief Justice John Roberts. He “may be reluctant to use whatever power the conference has against his colleagues,” Stephen Gillers, a legal ethics expert at the NYU School of Law, said in an email.

What about presidential immunity?

Biden is also calling for a constitutional amendment that would limit the Supreme Court’s recent decision granting former President Donald Trump — and all other presidents — broad immunity from prosecution.

The amendment would “make clear that there is no immunity for crimes committed by a former president while in office,” Biden wrote in a Washington Post opinion piece. “We are a nation of laws – not of kings or dictators.”

It wouldn’t be the first time — the Constitution has been amended about five more times in U.S. history to overturn a Supreme Court decision, Geyh said.

But constitutional amendments have even higher hurdles than new laws. The proposal must be supported by two-thirds of both the House and Senate and then ratified by three-quarters of state legislatures.

No new amendments have been adopted in more than 30 years. Republican House Speaker Mike Johnson has called Biden’s proposal a “dangerous gambit” that would be “dead on arrival in the House.”

Biden has resisted other calls to reform the Supreme Court

Biden, the former chairman of the Senate Judiciary Committee, has long resisted calls to reform the Supreme Court.

In 2021, he fulfilled a campaign promise by convening a commission to study potential changes to the court. It was not accused of making recommendations and warned that excessive changes could erode democracy.

The latest proposals come years later, and amid growing outrage among Democrats over Supreme Court opinions that overturned key decisions on abortion rights and federal regulatory powers. There is also a hotly contested presidential election against Trump.

While Biden’s ideas are unlikely to pass, they may draw voters’ attention. Vice President Kamala Harris, whom Biden endorsed for president after dropping out of the race, supported the proposal.

However, it is being blasted by conservatives like activist Leonard Leo, who said in a statement: “It’s about Democrats destroying a court they don’t agree with.”