Gun control advocates sputter at their own impotence. The National Rifle Association is politically ascendant. And President Barack Obama pledges to safeguard the Second Amendment in his first official response to the deaths of at least 12 people in suburban Denver.

Once, every highly publicized outbreak of gun violence produced strong calls from Democrats and a few Republicans for tougher controls on firearms.

Now those pleas are muted.

It's been more than a decade since gun control advocates had a realistic hope of getting legislation passed.

In 1994, Congress approved a 10-year ban on military-style assault weapons. Some Democrats came to believe it contributed to their loss of the House months later.

By 2004, when the assault weapon ban lapsed, congressional Democrats made no serious attempt to pass an extension.