A mass release of Guantanamo Bay detainees announced Monday will likely affect negotiations of this year’s National Defense Authorization Act, pushing lawmakers to keep tighter transfer restrictions in place, according to one expert.

Justin Johnson, an analyst with the Heritage Foundation, said aggressive moves by the administration, like the transfer of 15 detainees this week, will make it harder for those who support closing the detention center to make their argument and likely increase restrictions on transfers as House and Senate staffers negotiate differences between the two versions of the bill while lawmakers are in their home states.