David Kopel, an associate professor at Denver University and a policy analyst at the libertarian CATO Institute, said he warned 20 years ago that an assault weapons ban based on "superficial, cosmetic" standards would fail and was right.

The new assault weapons ban being considered by the Senate, he
said, was similarly flawed.

Saying assault weapons are only for mass murder is "libel" against police officers and others who use them for self-defense, Kopel argued. He went on to suggest both armed guards in schools and allowing teachers with concealed-carry permits to carry their weapons on campus, as is allowed in Utah.

"If we want to save lives, armed defense is the best choice," he said.