US President Joe Biden has unveiled a sweeping proposal to reform the Supreme Court, calling on lawmakers to establish term limits and form an ethics code "to restore trust and accountability" on its nine justices.

The conservative-leaning court has become a political battlefield in recent years, with its nine justices - unelected and able to serve for life - playing a powerful role in American life on everything from abortions to the environment.

Mr Biden has also called on lawmakers to pass a constitutional amendment limiting presidential immunity, a move which would reverse a recent Supreme Court decision.

Efforts to reform the court are unlikely to be passed by the US Congress.

Democrats, however, hope that pushing for reform can help galvanise voters ahead of the November 2024 election.

The Supreme Court has ruled on a string of historic cases in the last two years, starting with ending the constitutional right to abortion in June of 2022.

At the same time, it has been dogged by allegations of judicial ethics violations, particularly after journalists investigated Justice Clarence Thomas for not reporting gifts.

In an opinion piece published in the Washington Post on Monday morning, Mr Biden said that "what is happening now is not normal".

"It undermines the public's confidence in the court's decisions, including those impacting personal freedoms," he wrote in the Post. "We now stand in a breach."

To address these concerns, Mr Biden has proposed ending lifetime appointments to the court.

Instead, he believes that sitting presidents should appoint a new justice to the court every two years, who would then serve an 18-year period.

Reform advocates have previously suggested that staggered 18-year-term limits would help depoliticise the court and make it more balanced and representative of the population.

Additionally, Mr Biden is pressing Congress to establish a new code of ethics that would force justices to disclose gifts and avoid overt political activities.

While the court released a code of ethics for the first time in is history last year, the code does not have any enforcement mechanism.

"Every other federal judge is bound by an enforceable code of conduct," the president wrote. "There is no reason for the Supreme Court to be exempt."

Lastly, Mr Biden hopes to pass an amendment to the US constitution that would reverse a 1 July ruling in which the Supreme Court said that Donald Trump and other former presidents are immune from criminal prosecution.

In the controversial ruling, the court's justices found that a president has immunity for "official acts" but is not immune from "unofficial acts".

In his opinion piece, Mr Biden said that the proposed amendment - which he has dubbed the "No One is Above the Law" amendment" - would "make clear that there is no immunity for crimes a former president committed while in office."

"I share our founders' believe that the president's power is limited, not absolute," he wrote. "We are a nation of laws - not of kings or dictators".

Republicans have pushed back on efforts to reform the court.

On Sunday, for example, South Carolina Senator Lindsey Graham told CBS, the BBC's US partner, that Democrats made no effort to do so when a more liberal-leaning group of justices were "pumping out opinions they liked."

Earlier this month, Trump also described efforts to reform the court as an "illegal" and "unconstitutional" attack on the "sacred" institution.

"The Democrats are attempting to interfere in our presidential election, and destroy our justice system, by attacking their political opponent, me, and our honourable supreme court," he wrote. "We have to fight for our fair and independent courts, and protect our country."

Mr Biden is expected to address his proposed reforms at an event in Austin, Texas later on Monday afternoon.