Supreme Court nominee Merrick Garland headed back to the Senate Tuesday to meet with four senators and make his case for why he should be the next justice. And one member of the party opposing his nomination was impressed.

“My meeting today with Judge Garland left me more convinced than ever that the process should proceed,” said Sen. Susan Collins, R-Maine, who has been critical of GOP leadership’s decision not to give Garland’s nomination a hearing or a vote.

Republicans, led by Senate Majority Leader Mitch McConnell, have vowed not to consider Garland, whom President Barack Obama nominated to the high court following Justice Antonin Scalia’s death in February.

The GOP senators have argued the American people should decide the direction of the court in choosing the next president. Collins, and Sen. Mark S. Kirk, R-Ill., have been the two main voices in the caucus calling for the nomination to move forward.

“I am not optimistic that I will be changing minds on the issue,” Collins said. “But I think if more of my colleagues sit down with Judge Garland, that they are going to be impressed by him.”  

Collins stopped short of saying Garland’s meetings with Republicans would change their positions, noting “It’s always hazardous to predict what one’s colleagues are going to do.”

Everything You Need to Know About the Supreme Court Battle 

On the floor Tuesday, Senate Minority Leader Harry Reid, D-Nev., listed 16 senators including Collins, who have agreed to meet with Garland, who is the chief judge of the Court of Appeals for the D.C. Circuit. Democrats argue that a meeting is the first step toward backing down, but Republicans say otherwise.  

Senate Majority Leader Mitch McConnell, R-Ky., reiterated Tuesday that there has been no change in the number of Republican senators — 52 out of 54 — who have said the hearings and appointment should wait until next year.  

McConnell declined to comment on conservative groups criticizing GOP senators who agreed to meet with Garland, including Collins and Sen. John Boozman, R-Ark., who sat down with the D.C. jurist for roughly 20 minutes Tuesday.  

Adam Brandon, CEO of the conservative group FreedomWorks, blasted Collins in a statement saying, “We just can’t trust Susan Collins’ judgment.” Brandon also criticized Boozman in a statement Monday, saying, “It makes no sense” for Boozman to meet with Garland and adding, “This is not the time for squeamishness or timidity.”  

Boozman said in a statement following his meeting that he conveyed he does not believe the Senate should consider Garland’s nomination.  

“My position is firm,” said Boozman. “That means I will not advocate for hearings or a vote, nor will I support filling the vacancy with President Obama’s pick after the election.”  

Other Republicans who agreed to meet with Garland said they will convey the same position. Sen. Mike Rounds, R-S.D., said he said he would meet with Garland as a “courtesy,” and Sen. Bill Cassidy, R-La., said his meeting with Garland would be a “social visit.” Rounds, Cassidy, and Sen. James Lankford, R-Okla., who has also agreed to sit down with Garland, all said their meetings would not cause them to change their minds.  

But Democrats remain convinced that Republicans will relent, and the first step is a face-to-face with the nominee. Democrats also have some procedural maneuvers in their arsenal, including a motion to discharge Garland’s nomination from the Senate Judiciary Committee. But, for now, Democrats are keeping up pressure on Republicans to act.  

So far Republicans are not relenting, despite the number agreeing to sit down with Garland. Judiciary Chairman Charles Grassley spoke with Garland Monday evening and invited the judge to breakfast, at a time to be determined. A Judiciary Committee aide said the two would discuss why the Senate will not consider a Supreme Court nominee until next year.  

Niels Lesniewski contributed to this report. Get breaking news alerts and more from Roll Call on your iPhone or Android.