President Trump said proposals to expand the number of Supreme Court justices will " never happen."

Several Democratic presidential candidates have entertained the idea of packing the courts.

Historically, the Supreme Court's number of justices has fluctuated.

WASHINGTON — President Donald Trump said proposals from a number of Democrats to expand the number of Supreme Court justices will "never happen."

Several Democratic presidential candidates have embraced the prospect of "court packing" and increasing the number of Supreme Court justices beyond nine, citing anger with how Republicans in the Senate and the White House have reshaped the federal courts over the past few years.

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During a joint press conference with Brazilian President Jair Bolsonaro on Tuesday, Trump said he would not entertain the idea of expanding the Supreme Court.

"The only reason they're doing that is they're trying to catch up," Trump said of Democrats. "So if they can't catch up through the ballot box by winning an election they want to try doing it in a different way."

"We would have no interest in doing that whatsoever," he added. "It'll never happen. It won't happen. It won't happen I guarantee you for six years."

South Bend, Indiana, Mayor Pete Buttigieg explicitly endorsed the idea of adding more justices to the Supreme Court, while other candidates have expressed openness to the prospect.

California Sen. Kamala Harris said, "We are on the verge of a crisis of confidence in the Supreme Court."

"We have to take this challenge head on, and everything is on the table to do that," she added.

Former Texas Rep. Beto O'Rourke, who announced his presidential run last week, said at a campaign event he would consider changes to the courts.

"What if there were five justices selected by Democrats, five justices selected by Republicans, and those ten then picked five more justices independent of those who chose the first ten?" O'Rourke said. "I think that’s an idea that we should explore."

The Supreme Court's number of justices is not fixed and has changed throughout US history, leaving the door open for Democrats looking to change things in their favor.

During the final years of the Obama administration, Senate Majority Leader Mitch McConnell blocked the confirmation of scores of federal judgeships, including Merrick Garland, a nominee for the Supreme Court.

Since Trump has become president, the high number of vacancies has allowed Republicans to confirm lifetime-appointed judges at a breakneck speed, including two Supreme Court justices.