Sen. Steve Daines of Montana is leading a new Republican campaign to block President Obama from fulfilling a campaign promise to close the detention center at Guantanamo Bay.

Daines introduced a bill Thursday that would ban the transfer or release of Guantanamo Bay detainees until either the end of this year or enactment of the 2017 National Defense Authorization Act. If passed, it would kill any chance the president has of closing the prison before leaving office.