The House on Wednesday adopted an amendment to the 2015 national defense authorization that would keep intercontinental-range ballistic missiles in warm status past 2021.
"Warm" status means that the missiles will be kept empty but still capable of future active use.
"First and foremost, we don't know what the future holds and whether it will be in our strategic and security interests to shut down some of our silos 7 years from now," said amendment sponsor Rep. Steve Daines (R-Mont.), who is running for Senate.
But Rep. Adam Smith (D-Wash.), the top Democrat on the House Armed Services Committee, said that the amendment would micromanage Defense Department decisions about the nation's nuclear weapons.
"DOD should not be forced into a position of saying if a silo exists it has to be maintained forever, which is basically what this amendment says," Smith said.
Heritage Action, an influential conservative group, urged lawmakers to support the amendment to maintain the U.S. nuclear arsenal.
"All other nuclear powers are increasing the size of their arsenals. Maintaining ICBM silos warm would allow the U.S. to maintain flexibility to respond to unexpected strategic developments in a shorter time frame than if the U.S. had to rebuild the silos," Heritage Action's key vote alert reads.