The discussion comes a day after Connecticut Democrat Christopher S. Murphy waged a nearly 15-hour filibuster on the Senate floor, demanding action on gun legislation in the wake of a mass shooting that left 49 dead in an Orlando gay nightclub. About 40 senators, virtually all of them Democrats, joined him on the floor to ask questions. Murphy said Thursday he expects every Senate Democratic office to work throughout the weekend to secure GOP support for the measures. “There is going to a fury of advocacy that comes into Republicans’ members offices that will dwarf that of the NRA,” he said.

President Barack Obama, in Orlando to meet with the families of the shooting victims, said their collective grief “is beyond description,” and called again for new federal gun-control measures.

“Our politics have conspired to make it as easy as possible for a terrorist … to buy extraordinary powerful weapons and they can do so legally,” Obama said, noting that Florida shooter claimed allegiance to the Islamic State.

In the Senate, Dianne Feinstein, D-Calif., pushed the amendment that would prohibit suspected terrorists on government watch lists from purchasing guns. She said at a Thursday news conference that her measure has the support of the White House.

Cornyn is advancing a similar measure that would create a waiting period, not an outright ban on selling guns to those on watch lists. That version of the measure is supported by the National Rifle Association. Both proposals, rejected in December 2015, will be considered again Monday.