US Supreme Court's Ginsburg says cancer has returned, but won't retire

US Supreme Court Justice Ruth Bader Ginsburg, the 87-year-old anchor of its liberal wing, has said on Friday that she is undergoing chemotherapy for a recurrence of cancer but will remain on the bench.

Ginsburg, one of the four liberal justices on the nine-member court, said a biopsy in February had revealed lesions on her liver.

Ginsburg said a course of immunotherapy had proved unsuccessful but chemotherapy was "yielding positive results."

"I have often said I would remain a member of the Court as long as I can do the job full steam," she said in a statement. "I remain fully able to do that."

READ MORE: US Supreme Court Justice Ginsburg recovering after gallbladder treatment

Under Trump administration's watchful eye

Ginsburg's health is closely watched as President Donald Trump's administration seeks an opportunity to appoint a new justice who would tilt the court in a more solidly conservative direction, potentially shifting US law and social policy for decades.

Supreme Court justices serve until they die or voluntarily retire, and Ginsburg has clung to her position despite her age, aware that if she leaves it could change the US judicial landscape.

Ginsburg, who was appointed by President Bill Clinton in 1993, is the senior liberal justice on a court that leans conservative by a 5-4 margin.

Together with moderate-conservative Chief Justice John Roberts often acting as a swing vote, the four liberals have prevented a reversal of longstanding abortion rights, rebuked stronger executive powers for the president and staved off greater involvement of religion in public life.

Ginsburg has suffered at least three previous bouts with cancer over the past two decades, including colon cancer and lung cancer.

She said she began immunotherapy in May after the biopsy in February revealed the lesions on her liver. When that proved unsuccessful she began chemotherapy.

"My most recent scan on July 7 indicated significant reduction of the liver lesions and no new disease," Ginsburg said.

"I am tolerating chemotherapy well and am encouraged by the success of my current treatment," she said. "I will continue bi-weekly chemotherapy to keep my cancer at bay, and am able to maintain an active daily routine.

"Throughout, I have kept up with opinion writing and all other Court work."

Ginsburg said that her brief hospitalisation this week for infection was unrelated to the recurrence of cancer.

Setback rulings for Trump

Asked Tuesday at a White House press conference about Ginsburg's health, Trump said, "I wish her the best ... She's actually given me some good rulings."

Trump has welcomed some of the Supreme Court's rulings, but more often over the past three years it has dealt his administration setbacks – on his immigration policies and, more recently, his bid to prevent his finances from being made public.

Both Trump's Republicans, as well as Democrats, have made the balance of the court a campaign issue for November's presidential election.

Trump, who has already appointed two justices to the court, said in June he was planning to release a list of potential candidates for the next vacant seat if he is reelected.

"If given the opportunity, I will only choose from this list, as in the past, a Conservative Supreme Court Justice," he tweeted.

Feminist hero

Democrats for their part have sought to mobilise voters, warning that Trump should not be allowed to name another justice.

Hugely popular with Democrats, Ginsburg has become a feminist hero and an unintentional social media icon fondly known as "The Notorious RBG," a riff on slain rapper The Notorious BIG.

She has been hospitalised several times in recent years, including for two days in May to remove gallstones. 

But her hospital stays have always seen her actively participating in court activities by teleconference.

Ginsburg noted that she is able to “maintain an active daily routine” and that throughout her treatment she has “kept up with opinion writing and all other Court work.”

READ MORE: US Supreme Court Justice Ginsburg recovering after gallbladder treatment