WASHINGTON — (CNN) Supreme Court nominee Judge Merrick Garland on Tuesday will have his first meeting with a Republican senator when he sits down with Mark Kirk of Illinois, a centrist running for re-election in a Democratic-leaning state.

The meeting comes as Garland faces criticism from one Democratic senator, who is also running for re-election in a swing state, over a ruling in a campaign finance case that led to the rise of super PACs. Sen. Michael Bennet of Colorado said Garland’s views in the case were “wrongheaded.”

Most Republicans are refusing to meet with President Barack Obama’s court pick, arguing a nominee to replace the late conservative Justice Antonin Scalia should be chosen next year by whoever wins the White House this fall.

The Kirk session is a highpoint for Democrats who are pursuing an aggressive political and public relations strategy to pressure individual GOP senators to agree to a confirmation vote for Garland. Democrats hope it will compel other Republicans to open their doors first to a meeting with Garland and eventually to a vote on his confirmation.

“Sen. Kirk has made a judgment that it is the right thing to do. I hope each individual senator will be held accountable for their actions on this nomination. And that means not only whether you vote for or against but the process you use,” said Sen. Ben Cardin, D-Maryland, after he met with Garland Monday.

A handful of other Republicans have said they will meet with the judge but only Kirk and Sen. Susan Collins of Maine, who is also a moderate Republican, have backed a full confirmation process going forward.

Kirk is considered perhaps the most endangered GOP incumbent senator as he runs for a second term in Illinois against Democratic Rep. Tammy Duckworth, a war veteran. He was one of the first Republicans to agree to meet with Garland and eventually announced the judge should get hearings and a vote on confirmation.

“Just man up and cast a vote,” Kirk told WLS radio a week ago. “The tough thing about these senatorial jobs is you get ‘yes’ or ‘no’ votes. Your whole job is to either say, ‘yes’ or ‘no,’ and explain why.”

Cardin called the GOP’s refusal to hold hearings an “abuse of power” and said Sen. Mitch McConnell, R-Kentucky, needs to “deal with his responsibility as majority leader” and schedule hearings and a vote.

While Garland has drawn heavy criticism from the conservatives for his positions on gun control and executive branch authority, he has also gotten complaints from progressives who say he is not liberal enough.

One sign of that concern was on display at an event at the University of Denver Law School last week, where Bennet was asked about Garland’s stance on the controversial 2010 Citizens United campaign finance reform case that opened the door to large scale donations to political organizations from corporations and labor unions, something many Democrats oppose.

While Garland didn’t rule directly on Citizens United, he did join eight other circuit court judges in expanding its scope later that year in Speechnow vs. Federal Election Commission, which allowed individuals to make unlimited donations to political organizations. The case led to the surge of super PACs that now dominate elections.

“I have not read his opinion, his wrongheaded opinion in Citizens United. I haven’t read it. Obviously, I won’t comment on it except that it’s one of the opinions that I’m going to read before I sit down to talk to him,” Bennet said. “I have read the Supreme Court’s decision in Citizens United and I think it’s been a devastating blow to our democracy.”

Video of his remarks were covertly recorded and provided to CNN by a tracker for America Rising, a conservative political organization that says it is committed to “exposing the truth about Democratic politicians.”

Bennet’s criticism of Garland’s views in this case may appeal to the liberals in his state he needs to win re-election this fall. Bennet is considered the most vulnerable Democrat running in a purple state, which two years ago tossed out a big name incumbent Democrat, Sen. Mark Udall, in favor of a conservative Republican.

Bennet, who otherwise has been laudatory of Garland, has been very involved in campaign finance issues as he used to chair the Democratic Senatorial Campaign Committee, which raises money and works to elect Democrats to the Senate.

Adam Bozzi, a spokesman for Bennet, wouldn’t elaborate on the senator’s concerns about Garland’s position but said that Bennet “disagrees with the Supreme Court’s Citizens United ruling and attempts to expand it generally” and that he “looks forward to reading the decision, meeting with him and learning more specifics” from the judge.

Garland also met Monday morning with Sen. Joe Donnelly, an Indiana Democrat. During a photo-opportunity for journalists, an alarm sounded from U.S. Capitol Police saying it was conducting a “shelter-on-place” drill and that no one should leave their offices.

Donnelly apologized to Garland for the loud disruption that and said “it just happens to coincide” with the judge’s visit.

The drill foreshadowed a real shelter-in-place occurrence later in the day when a gunmen tried to enter the U.S. Capitol Visitor Center and was shot by police.

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