Mitt Romney, who voted against confirming Ketanji Brown Jackson last year, says he has not decided whether he will support elevating her to the Supreme Court

 Republican Sen. Mitt Romney told CNN's Kasie Hunt that he has not decided whether he will vote to confirm Judge Ketanji Brown Jackson to serve on the U.S. Supreme Court.

Romney, who voted against confirming Jackson to the U.S. Court of Appeals for the D.C. Circuit last year, said that he has started a "much deeper dive than ... during the prior evaluation."

"I'll complete that analysis and then reach a decision," he said, noting that he has not made a choice yet.

Even if no GOP senators choose to lend their support, the Senate Democratic caucus could still place Jackson on the high court if they all vote to confirm and then Vice President Kamala Harris casts a tie-breaking vote.

GOP Sens. Lisa Murkowski of Alaska, Susan Collins of Maine, and Lindsey Graham of South Carolina voted to confirm Jackson last year.

Sen. Ben Sasse, who was listed as "Not Voting" on the confirmation vote last year, issued a statement last week in which he called Jackson "an extraordinary person" but said that he will not vote in favor of confirming her to the high court. 

"Judge Jackson has impeccable credentials and a deep knowledge of the law, but at every turn this week she not only refused to claim originalism as her judicial philosophy, she refused to claim any judicial philosophy at all," Sasse said in the statement. "Although she explained originalism and textualism in some detail to the committee, Judge Jackson refused to embrace them or any other precise system of limits on the judicial role," he said.