A Republican senator from a northern border state is leading a charge to bar federal border authorities from paroling into the United States any illegal immigrant determined to be a possible national security threat.

Sen. Steve Daines (R-MT), alongside eight other Republican senators, debuted the Safeguarding Americans From Extremist Risk at the Border Act on Monday, which would prevent U.S. Customs and Border Protection agents from allowing illegal immigrants on the FBI terrorist watchlist or those labeled “special interest” individuals from being admitted.