1. This program only applies to groups that Congress has authorized military force against. 2. There's no need to drone strike/air strike people in the U.S. instead of sending in agents/troops in armored vehicles to (try to) arrest them. They didn't send an F-16 to launch a missile at Waco. 3. If they decided that some conservatives were waging an insurrection against the government, they would not need the Patriot Act, NDAA, or some DOJ memo to go after them. Legal ability to go after treason/sedition is well-established. The inevitable public backlash very much keeps this in check.