WASHINGTON — A key Republican senator whose vote could help determine whether Brett Kavanaugh is confirmed to the Supreme Court spoke favorably of him on Tuesday, praising the jurist for prior comments on a landmark abortion ruling and an opinion keeping in place major provisions of Obamacare.

Sen. Susan Collins, R-Maine, a moderate who supports abortion rights and has said she could not back a nominee who opposed Roe v. Wade, told NBC News she was "glad" about remarks Kavanaugh made more than 10 years ago that the 1973 ruling legalizing abortion was "settled precedent."

Her comments offer a preview of the rationale she might use in eventually backing his confirmation — a would-be critical vote for the GOP to maintain its slim Senate majority.

"Back then, he said that he considered Roe to be settled precedent and that is my judgment as well, so I was glad to hear him say that at that time," Collins said, adding that she would raise the issue when she meets privately with him as part of the confirmation process.

In 2006, during his confirmation hearing for a seat on the Court of Appeals for the District of Columbia Circuit, Kavanaugh said he "would follow Roe v. Wade faithfully and fully." Kavanaugh called it a "binding precedent of the court."

Collins also said Tuesday she found Kavanaugh's dissent "notable" in a 2011 decision by his Circuit Court in which the senator pointed out he did not argue for striking down Obamacare's ban on health insurers' discriminating against those with pre-existing conditions or for doing away with the individual mandate. Kavanaugh, in his dissent, said he believed the court did not have jurisdiction in the case challenging the Affordable Care Act.

READ: How Kavanaugh could change the court's balance of power

"I need to read very thoroughly that decision, and I'm sure that'd be an issue that we will talk about," Collins said. “I care deeply about the pre-existing conditions that are part of the Affordable Care Act."

She added, "He clearly has very impressive credentials and extensive experience having served for more than a decade on the D.C. Circuit Court. I know that he is held in high regard by many attorneys and judges whom I know."

With a razor-thin 51-49 Senate majority, Republicans can't afford to lose more than two votes in Kavanaugh's confirmation if Democrats are united against him.

Such a slim margin for error means the fate of Kavanaugh's nomination could be in the hands of Collins and Lisa Murkowski, R-Alaska, as well as a handful of Democrats from states that voted for the president in the last election and who are facing the voters themselves this fall (including Sens. Joe Donnelly of Indiana, Joe Manchin of West Virginia, Heidi Heitkamp of North Dakota, and possibly Doug Jones of Alabama, who is not up for re-election in his very conservative state until 2020).

Murkowski, offering more guarded comments, told reporters Tuesday she'd never met Kavanaugh but was looking forward to sitting down with him. She didn't answer questions about his 2006 comments about Roe v. Wade.

Kavanaugh, for his part, spent Tuesday — his first day since being nominated by Trump — on Capitol Hill, embarking on a series of meet-and-greets with Republican senators to win their support.

The facetime with lawmakers marks the beginning of the campaign by the nominee and the White House to secure the 51 Senate votes needed for Kavanaugh to be confirmed this fall — although he did not meet with Collins.

Kavanaugh arrived on the Hill shortly after 11 a.m., alongside Vice President Mike Pence and former Sen. Jon Kyl, R-Ariz., whom the White House had tapped to shepherd the nominee through the get-togethers with lawmakers.

Kavanaugh met first with Senate Majority Leader Mitch McConnell, R-Ky., who said, "I think the president made an outstanding nomination."

Pence, standing alongside McConnell and a beaming Kavanaugh, called the judge "a man of impeccable credentials and character" and said he's confident senators in both political parties will see the pick as "the most qualified and the most deserving nominee to the Supreme Court."

Kavanaugh didn't respond to shouted questions from reporters.

Later in the day with Senate Judiciary Committee Chairman Chuck Grassley, R-Iowa, who said Kavanaugh’s confirmation proceedings were "going to be thorough and going to be done right, and we’ll do what we can to accommodate everybody's interests in the end."

If confirmed, Kavanaugh would make the Supreme Court solidly conservative, joining Chief Justice John Roberts and Justices Clarence Thomas, Samuel Alito, and Neil Gorsuch in a potential five-vote conservative majority.