Updated 2:30 a.m. ET Thursday:
Nearly 15 hours: The Associated Press reports that's how long Connecticut Sen. Chris Murphy and his Democratic colleagues held the floor before yielding early Thursday, with a pledge that he would aggressively press for a legislative response to the Orlando, Fla., mass shooting. Murphy has been upset with congressional inaction on gun violence.
Senate Democrats say they are bringing Senate business to a halt in an effort to force some action on gun control.