President Trump met with a bipartisan group of six senators at the White House Thursday night to discuss the Supreme Court vacancy left by the looming retirement of Justice Anthony Kennedy.

The president met in person with Senate Judiciary Committee chairman Chuck Grassley, R-Iowa; Susan Collins, R-Maine; Lisa Murkowski, R-Alaska; Heidi Heitkamp, D-N.D.; Joe Manchin, D-W.Va.; and Joe Donnelly, D-Ind.

White House press secretary Sarah Sanders said in a statement, "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 on this important nomination.”

Collins, Donnelly, Heitkamp, Manchin and Murkowski are seen as potential "swing" votes in the battle over Kennedy's replacement. Republicans currently hold a 51-49 majority in the Senate, a slim margin that is effectively 50-49 in the absence of the John McCain, who's been recovering from brain cancer treatment. That means Republicans effectively cannot lose any support for President Trump's pick.

Murkowski has vowed a careful vetting of Trump's nominee, saying, "there is no doubt that the president's nominee to succeed Justice Kennedy can expect exacting scrutiny from the Senate and that is the standard I will apply ... "

Collins, meanwhile, declared that the landmark Roe v. Wade decision that codified abortion rights is "settled law," adding, "I always look for judges who respect precedent."

Despite the difficult balancing act facing Republicans, all three Democrats who met with Trump Thursday are facing difficult re-election races and could find it difficult to oppose the president's second pick.

Heitkamp was meeting with Trump one day after he campaigned for her opponent, U.S. Rep. Kevin Cramer, in North Dakota's Senate race. In a statement, Heitkamp said she and Trump "had a solid discussion about the Supreme Court vacancy," adding that she "stressed the importance of nominating someone to the Supreme Court who is pragmatic, fair, compassionate, committed to justice, and above politics – traits that match Justice Kennedy and which I know are important to North Dakotans."

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

All five "swing" senators voted to confirm Trump's first nominee to the court, Neil Gorsuch, last year.

Fox News' Jason Donner, Chad Pergram and The Associated Press contributed to this report.