A top Republican leader pushed back against a proposed presidential order that would reexamine more aggressive interrogation techniques against terrorist detainees, telling reporters that torture is illegal.

Employing waterboarding again "would take a change in the law, and Congress is on record," Senate Republican Conference Chair John Thune told reporters Wednesday afternoon. "With respect to torture, that's banned… we view that to be a matter of settled law."

The Trump White House is circulating a draft executive order that would remove the prohibitions on CIA black sites, which were last employed under the George W. Bush administration. It would also direct a review of more aggressive interrogation techniques against detainees.

Congress passed a law in 2015, authored by Sens. John McCain and Dianne Feinstein, banning any interrogation techniques involving the use or threat of force, as well as any techniques not explicitly outlined in the publicly-available U.S. Army Field Manual.

"This is a debate we've had already," Thune said at a gathering of Republican lawmakers in Philadelphia. "Now if the administration has a proposal that they want Congress to take a look at, certainly we're willing to take a look at what it might be that they're suggesting."

—Tim Mak