Idaho Sen. Jim Risch defended a planned filibuster against allowing a vote on the president's gun legislation to Anderson Cooper tonight, but also said it won't work. "It is a procedural method by which if you're successful you can stop passage of a bill," Risch told Cooper. But, he said, "I think there's clearly 60 votes to override a filibuster. There's going to be debate on this."

On the same program, Cooper interviewed former Congresswoman Gabrielle Giffords and the mother of a slain 6-year-old Sandy Hook Elementary School student; both spoke out in favor of the proposal for universal background checks for gun purchasers. Pressed by Cooper, Risch said, "No. 1, it doesn't work, and No. 2, it's placing a burden on a law-abiding citizen." He said, "It isn't that it goes too far - it's just ineffective."

Risch said, "We need to enforce the laws we have. ... We ought to focus on keeping the guns out of the hands of convicted felons and people who have mental illness."

Cooper said Risch was the only one of the 14 senators who have threatened to filibuster who agreed to appear on the program.