Murphy was seeking a vote on legislation that would expand background checks required for weapons purchases, and on a measure sponsored by Senator Dianne Feinstein of California that would allow the U.S. to ban sales of guns and explosives to people listed on government watch lists of suspected terrorists. The Feinstein Amendment came to the Senate floor one day after 14 people were killed by Rizwan Farook and Tashfeen Malik in the San Bernardino terrorist attack in December 2015, but failed on a party-line vote, with Democrats in favor and Republicans opposed.