WASHINGTON (Reuters) - With 86-year-old liberal Justice Ruth Bader Ginsburg enduring a series of health scares, the question of whether President Donald Trump will get to make yet another U.S. Supreme Court appointment before the 2020 election lingers as the nine justices prepare to begin their new term next week.

FILE PHOTO: U.S. Supreme Court Justice Ruth Bader Ginsburg waves to guests after a reception where she was presented with a honorary doctoral degree at the University of Buffalo School of Law in Buffalo, New York, U.S., August 26, 2019. REUTERS/Lindsay DeDario/File Photo

The justices, held a private conference on Tuesday to discuss taking new cases after a three-month summer break, open their next nine-month term on Monday, with arguments pending in the coming weeks in major cases involving gay and transgender rights, immigration and other issues.

Trump, who took office in 2017 and is seeking re-election next year, already has appointed two justices - conservatives Brett Kavanaugh and Neil Gorsuch - who have pushed the court further to the right.

The court has a 5-4 conservative majority, and two of the four liberal justices are over 80 years old, including Stephen Breyer, who turned 81 last month. Ginsburg, a justice since 1993, underwent radiation therapy in August to treat a cancerous tumor on her pancreas after having two cancerous nodules in her left lung removed last December.

The stakes could not be higher for the Supreme Court.

With Trump’s fellow Republicans in control of the Senate, which wields confirmation power over federal judicial nominations, Majority Leader Mitch McConnell is well placed to push through another Trump Supreme Court appointment even if the vacancy arises close to the November 2020 election.

If Trump, running for re-election, were to win a second four-year term next year, he potentially would be able to replace both Ginsburg and Breyer, leaving the court with a rock-solid 7-2 conservative majority, possibly for decades to come. That could mean a rightward shift on numerous matters including abortion restrictions, expanding gun rights, blunting the advance of LGBT rights, maintaining the death penalty and bolstering the interests of corporations.

McConnell, who has made confirmation of Trump judicial appointees a paramount priority, made clear his intentions when asked in May at an event in his home state of Kentucky what he would do if a Supreme Court vacancy arose in 2020.

“Oh, we’d fill it,” McConnell said.

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McConnell in 2016 refused to allow the Senate to act when Democratic former President Barack Obama nominated federal appellate judge Merrick Garland to fill a vacancy created by the death of conservative Justice Antonin Scalia - a move Democrats have described as the theft of a Supreme Court seat.

In justifying their inaction on Garland, McConnell and other Republicans argued that the Senate should not confirm a Supreme Court nominee during a presidential election year. Trump won the 2016 election and in 2017 named Gorsuch to replace Scalia.

‘ON MY WAY’

Ginsburg, who previously underwent treatment for colon cancer in 1999 and pancreatic cancer in 2009, is expected to be on the bench when the new term opens.

“I am on my way to being very well,” Ginsburg said on Aug. 31 during an appearance at a Washington event.

The diminutive and frail-looking justice also appeared in recent weeks alongside Justice Sonia Sotomayor at an event celebrating retired Justice Sandra Day O’Connor, 89, the first woman to serve on the court.

Compared to Ginsburg, who was a pioneering women’s rights lawyer before becoming a justice and has become something of an icon to American liberals, Breyer keeps a lower profile. His most recent public appearance was in London on Sept. 16. He is not known to have had any health scares since a bicycle fall in 2013 in which he fractured a shoulder.

Former senior Republican Senate aide Mike Davis, who runs a group called the Article III Project that he set up to support Trump’s judicial nominations, said he would expect Republicans to be energized by any potential election-year vacancy. But Davis said he also would expect Democrats to put up a fight.

“If people thought that Justice Kavanaugh’s confirmation fight was ugly, just wait until the next one,” Davis said, referring to contentious Senate hearings in which Kavanaugh denied allegations of decades-old sexual misconduct.

No president since Republican Ronald Reagan has appointed more than two justices to the Supreme Court. Reagan named three in his eight years as president, from 1981 to 1989. The last president to have had more than two Supreme Court appointments in his first term in office was Republican President Richard Nixon, who named four in that term running from 1969 to 1973.

Since Nixon was first elected, Republican presidents have filled 14 of the 18 Supreme Court vacancies that have arisen.

Liberal activists are resigned to the idea that Republicans would seize on any opening to expand the court’s conservative majority, even if a vacancy occurs close to the 2020 election.

“They would jump at the chance to make it (the conservative majority) 6-3. I don’t think it matters to them. It’s a raw power grab on their part,” said Christopher Kang, chief counsel at the liberal legal activist group Demand Justice.

If Senate Republicans push through a nomination - in particular in a scenario in which a Trump selection is confirmed after he loses the election but before a new president takes office - it would build momentum among Democrats for an idea promoted by some liberals for adding more seats to the court to loosen the conservative stranglehold, Kang said.