Sen. John Thune (S.D.), the No. 2 Senate Republican, said on Tuesday that he will oppose Ketanji Brown Jackson’s Supreme Court nomination.

Thune’s opposition, while expected, is the latest indication that Republicans are hardening their stance on Jackson’s nomination.  

“I enjoyed meeting with Judge Jackson and respect her achievements, but I cannot in good conscience vote for a Supreme Court justice whose record indicates that she will allow her personal political opinions to shape her judicial decisions,” Thune said.  

Thune pointed to multiple issues, including her sentencing rulings, declining to take a stance on expanding the Supreme Court and questions about her judicial philosophy.  

The White House and Democratic senators have defended Jackson by noting her sentencing decisions are in the mainstream and that previous nominees haven’t taken a position on expanding the Supreme Court.  

Thune’s official announcement comes after he indicated to reporters on Monday that he would oppose her and Senate Minority Leader Mitch McConnell (R-Ky.) said last week that he would vote against Jackson. 

Democrats don't need GOP support to confirm Jackson as long as all 50 of their members support her and are present to vote, and Vice President Harris can break a tie. 

But Democrats are hoping to peel off at least one GOP senator. 

Republican Sens. Lindsey Graham (S.C.), Lisa Murkowski (Alaska) and Susan Collins (Maine) voted for her confirmation to the circuit court last year.