Democrats who voted for President Trump's first nominee to the Supreme Court, Joe Manchin of West Virginia, Joe Donnelly of Indiana and Heidi Heitkamp of North Dakota, met with the president Thursday to talk about the Supreme Court, according to White House press secretary Sarah Huckabee Sanders.

All three are facing difficult re-election races, in states that strongly supported Mr. Trump during the presidential election, and they could find it difficult to oppose the president's second pick.

Last year, Trump's first nominee to the court, Neil Gorsuch, was confirmed 54-45, with only these three Democrats voting in favor.

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Manchin indicated he was keeping an open mind. "I just think you have to go through a process," he said. "I want qualifications. Somebody that's well qualified, understands the Constitution and the rule of law."

Donnelly said he had a "good conversation" with Mr. Trump and "will thoroughly review the record and qualifications" of the nominee. Manchin called his meeting "productive."

Sanders also said in a tweet that the president's team also talked with "more than a dozen other Senators today as part of ongoing outreach to get views and advice from both sides of the aisle."

Senate Democrats have been arguing that Senate Majority Leader Mitch McConnell should not hold a confirmation hearing or vote on a candidate in an election year, attempting to use McConnell's logic in denying President Obama's appointee, Merrick Garland a hearing when he was nominated. McConnell responded, "This is not 2016. There aren't the final months of a second-term constitutionally lame-duck presidency with a presidential election fast approaching. We're right in the middle of this president's very first term."

At least one conservative agrees with Democrats that the confirmation vote should follow the election, rather than preceding it. Tony Perkins, president of the Family Research Council, a leading evangelical and conservative advocate, was among those suggesting it might make sense to put off a vote on the nominee. He said a vacancy on the court in 2016 helped boost enthusiasm among evangelicals for Trump.

"Part of me says I would like to see it after the election because I think it will just fuel the turnout and have more participation in the election," Perkins said.

Several Democratic senators considering 2020 presidential runs jumped into the debate Thursday, rallying from the steps of the Supreme Court. Sen. Cory Booker pledged a long-term battle to prevent Trump from rushing a conservative judge onto the court.

"We now must fight," the New Jersey Democrat said.

New York Sen. Kirsten Gillibrand said Kennedy's retirement sets up a situation where "women's lives are at risk."

Mr. Trump has said he would start the effort to replace Kennedy "immediately" and would pick from a list of 25 names that he updated last year.

McConnell declared that the Senate "will vote to confirm Justice Kennedy's successor this fall." But that left the timing open for debate.

Possible nominees being eyed include Thomas Hardiman, who has served with Trump's sister, now on senior inactive status, on the 3rd U.S. Circuit Court of Appeals in Philadelphia, and Raymond Kethledge, a federal appeals court judge who clerked for Kennedy. Also of interest are Amul Thapar, who serves on the federal appeals court in Cincinnati, lives in Kentucky and is close to McConnell; Brett Kavanaugh, a former clerk for Kennedy who serves on the federal appeals court in Washington, D.C.; and Amy Coney Barrett, who serves on the federal appeals court in Chicago.