Because they won’t.

Via Washington Secrets:

Americans like the idea of making every gun buyer face a background check, but most don’t think it will have the intended impact of cutting gun violence, according to a new national poll.

Rasmussen Reports revealed Tuesday that 51 percent believe that strict background checks won’t put the brake on violent crime. In fact, 6 percent believe it will spark even worse crime. Forty percent believe that background checks will help to decrease violence.