U.S. President Donald Trump would be expected to quickly name a Supreme Court nominee if there were an opening on the bench, White House Chief of Staff Mark Meadows told reporters on Air Force One on Wednesday.

Meadows also said the White House is glad Justice Ruth Bader Ginsburg, is out of the hospital and doing well after being treated for a possible infection.

Ginsburg, the 87-year-old anchor of its liberal faction, was discharged from a hospital on Wednesday, the court said.

She was admitted to Johns Hopkins Hospital in Baltimore early on Tuesday after first going to her regular Washington hospital with a fever and chills, and underwent an endoscopic procedure to clean out a bile duct stent she received nearly a year ago.

"Justice Ginsburg has been discharged from the hospital. She is home and doing well," said Kathy Arberg, spokeswoman for the court.

Originally, the court indicated she might stay in the hospital for several days while antibiotics were administered for a feared infection.

One of four liberals among the nine justices, Ginsburg's health is closely watched as Trump's administration seeks an opportunity to appoint a new justice who would tilt the court in a more solidly conservative direction, potentially shifting U.S. 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 U.S. judicial landscape.

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.

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

Election issue

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

Both Trump's Republicans as well as Democrats have made the balance of the court a key election issue.

Trump, who has already appointed two justices to the court, said in June that 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.

Democrats for their part have sought to mobilize 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 B.I.G.

She has been hospitalised several times in recent years, including for two days in May to be treated for a benign gallbladder infection.

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

It was not clear if she took part in court discussions overnight Monday on emergency petitions over the resumption of federal executions as a convicted murderer waited on death row in an Indiana prison.

But she joined dissents by the opposing minority when the court ruled five-to-four in favor of going ahead.

Hours later the murderer, Daniel Lee, was put to death, in the first federal execution in 17 years.

(With input from Reuters)

(Cover: U.S. Supreme Court Justice Ruth Bader Ginsburg at a University of Buffalo, New York, event, 2019. /Reuters)