The Hill explains: “With their hopes for a Brown yes vote now dashed, Democrats and watchdog groups are training their lobbying fire on GOP Sens. Olympia Snowe and Susan Collins, two Maine centrists who along with Brown have played decisive roles in a bevy of controversial summer bills. …Democrats also could lose the support of two centrist Democrats, Sens. Ben Nelson (Neb.) and Blanche Lincoln (Ark.) — who is locked in a tight reelection contest — making Republican support even more crucial to overcoming an expected GOP filibuster.”
In addition, Sen. Feinstein opposes the House version of the bill because of the NRA carve-out.