Sen. Lisa Murkowski announced Thursday that she would vote against confirming Pete Hegseth to lead the Pentagon, becoming the first Republican to oppose one of President Donald Trump’s Cabinet picks.

Maine GOP Sen. Susan Collins also voted against Hegseth. 

The Alaska Republican’s decision comes ahead of a crucial test vote to advance Hegseth’s nomination toward confirmation, according to the Associated Press. 

The Senate voted 51-49 to advance Hegseth's nominiation. The final vote will take place Jan. 24.