The nomination of Sen. Markwayne Mullin (R-KY) to be President Donald Trump’s next head of the Department of Homeland Security may hinge on Sen. John Fetterman (D-PA) in the face of opposition from Sen. Rand Paul (R-KY).

Paul, who chairs the Senate’s homeland security committee, will hold a Thursday vote to advance Mullin’s nomination to the full chamber, just one day after Paul eviscerated Mullin at the nominee’s confirmation hearing.