Meanwhile, the group has poured resources into an aggressive push for gun rights at the state level.
In 1981, for example, only two states allowed residents to easily obtain permits to tote concealed handguns in public, and only one required no permit. Now, in 35 states people can readily get concealed-carry permits, and four have no permit requirements.
The group also helped pass "stand your ground" laws in more than two dozen states, giving people expanded rights to fire in self-defense rather than first retreating.
Since 12 people were killed and 58 injured July 20 in Aurora, talk of enacting stricter gun control measures has revived in Colorado. "There will be gun control measures introduced," said Eileen McCarron, president of the pro-gun-control Colorado Ceasefire Capitol Fund. "Passed is a whole different matter."
Part of the NRA's power stems from memories Democrats have of two major political losses: the 1994 GOP takeover of the House of Representatives and Al Gore's defeat in the 2000 presidential election. According to political lore, both stem from Democratic support for gun control — a factor Spitzer said has been overstated.
Still, Democrats have since recruited candidates who are more friendly to gun rights.
Brian Malte, director of legislation for the Brady Campaign to Prevent Gun Violence, contends that the NRA has created an image of influence that exceeds reality. "There's a perception that, 'If I don't go with them, they'll knock me out.' But they don't do that," he said.
Liberal critics argue that there's little evidence the NRA's money makes much difference in a congressional race. A recent analysis in ThinkProgress by Paul Waldman, a contributing editor at the American Prospect, found that in 22 recent Senate races in which the NRA spent more than $100,000, its record was mixed: 10 of its candidates won and 12 lost.
At the same time, gun control advocacy groups have struggled to match the NRA in finances and influence. The Brady Campaign spends a little more than $3 million per year.
"We haven't done enough to match what the NRA has been able to accomplish," said Mark Glaze, director of Mayors Against Illegal Guns. Legislators who fear the NRA's wrath can't count on the same kind of financial and grass-roots support from the pro-gun-control side, he said.
An elected official, he said, could rightly ask: "What am I going to get from you people? Thanks for a job well done?"
Melanie Mason in the Washington bureau contributed to this report.