Judge Kavanaugh’s views on abortion have raised intense concern among abortion rights advocates, in part because of a dissent he wrote in a 2017 case, Garza v. Hargan, that drew widespread attention last fall. Ms. Collins said she talked to Judge Kavanaugh “at length” about the Garza case — the only abortion case in which he has rendered a decision.

In that decision, the United States Court of Appeals for the District of Columbia Circuit, on which Judge Kavanaugh serves, voted to allow an undocumented 17-year-old in immigration detention to seek an abortion without delay; the Trump administration had wanted to first transfer her to an adult sponsor for guidance.

In his dissent, Judge Kavanaugh wrote that while the appeals court was bound to obey Supreme Court rulings that said the Constitution protects a woman’s right to choose an abortion, those precedents nonetheless permit the government to apply “reasonable regulations that do not impose an undue burden.”

Ms. Collins has previously said that she will vote against any nominee who “demonstrates hostility” to Roe. In her meeting with Judge Kavanaugh, Ms. Collins said, “we talked at great length about precedent and the application of stare decisis” — the legal principle of standing by precedent — “to abortion cases.”

“We talked about whether he considered Roe to be settled law; he said that he agreed with what Justice Roberts said at his nomination hearing, in which he said that it was settled law,” she added.

Chief Justice Roberts testified before the Senate Judiciary Committee in 2005 that Roe was “settled as a precedent of the court, entitled to respect under principles of stare decisis.” However, he added, those principles “explain when cases should be revisited and when they should not.”

Abortion rights groups immediately jumped on the “settled law” comment, noting that, despite his confirmation hearing testimony, Chief Justice Roberts dissented when the Supreme Court struck down a Texas law that would have severely restricted access to abortion.