Sen. Rand Paul (R-Ky.) said Wednesday night that support for President Barack Obama’s drone program was “very scary and worrisome” and feared it could open a “Pandora’s box” about government’s power.

Paul was on CNN discussing his consideration of filibustering Obama’s nomination of John Brennan for CIA director, doubling down on his criticism of Brennan’s question-dodging regarding drone use at his confirmation hearing last week.