WASHINGTON (Reuters) - Even before the mass shooting on Friday at a Connecticut elementary school, gun control advocates were making a furious push to convince U.S. lawmakers that their long-ignored issue was a political winner.
Their argument was that support for restrictive new laws is not a career-ender for politicians and that they might even benefit at the polls by opposing the pro-gun rights National Rifle Association.
Gun control groups are attempting to turn upside-down the politics of guns after nearly two decades in which the pro-gun rights lobby has effectively blocked any major new gun restrictions. A ban on certain semiautomatic rifles known as assault weapons was allowed to expire in 2004.
Their success or failure could determine whether national legislation materializes after the massacre at Sandy Hook Elementary School in Newtown, Connecticut, that left 26 dead, including 20 children between the ages of 6 and 7.
At the center of the issue is New York City Mayor Michael Bloomberg, a gun control supporter who used his personal fortune to help defeat a little-known California Democrat who supported gun rights. Representative Joe Baca lost his reelection bid on November 6 after Bloomberg spent $3.3 million on the race.
"The side for reasonable gun laws has to make politicians who oppose them cringe in terror about their reelection prospects," said Jim Kessler, senior vice president for policy at Third Way, a Democratic group that looks for middle ground on gun control and other issues.
"The NRA has done that pretty well," Kessler said, "And the other side needs to do that, too. That's the fight they're in."
The November 6 elections brought more encouraging results to gun control advocates. The NRA's political arm spent $100,000 or more in each of at least seven races for the U.S. Senate, but its preferred candidate won in only one of them - Republican Jeff Flake prevailed in Arizona.
NRA President David Keene said in an NRA-produced video last month that the election results were an anomaly, driven by President Barack Obama's turnout of young voters and select other demographics.
"In normal circumstances, we would have made a huge difference," he said.
Some NRA members may have been complacent because Obama did little on gun control during his first term, Keene said. But he added the group, which is believed to have about 4 million members, was still strong enough to resist gun control efforts, with a "bipartisan majority" in the U.S. House of Representatives and Senate "that will stand up for us."
A Reuters/Ipsos poll in April found that 68 percent of Americans have a favorable view of the NRA. The organization has declined to comment on the massacre in Connecticut, which was among the most deadly U.S. school shootings, or potential fallout "until the facts are thoroughly known."
The gunman, Adam Lanza, used a long rifle as his primary weapon, the state's chief medical examiner said on Saturday. Nancy Lanza, his mother, legally owned two handguns and a military-style Bushmaster .223 M4 carbine, according to law enforcement officials.
Hours after the shootings, Obama tearfully said on national television that the country needs "meaningful action to prevent more tragedies," while Bloomberg urged him to send gun control legislation to Congress.
Politicians' caution over gun control dates to 2000, when Democratic presidential nominee Al Gore lost states such as Arkansas, New Hampshire and his home state of Tennessee - places where he was thought to have a chance, and where guns are popular.
Analysts debated endlessly whether Gore's full-throated support for tough gun laws helped to cost him the election. Enough Democrats thought so to convince the party the issue was not worth the risk.
Mass shootings have not made a difference in public opinion, according to polling research that shows a steady decline in support for gun control during the past two decades.
When the non-partisan Pew Research Center asked people their attitudes on guns in July, a week after 12 people were shot to death in a theater in Aurora, Colorado, opinions were little changed from April: 47 percent said it was more important to control guns, while 46 percent said protecting gun rights was more important.
The U.S. Constitution guarantees the right to bear arms.
Those numbers mask support for specific ideas, supporters of gun control say.
Mayors Against Illegal Guns, co-led by Bloomberg, paid for a poll of voters in the swing states of Colorado, North Carolina and Virginia. According to the results released this month, nine in 10 voters in each state supported universal background checks for gun owners; checks are not currently required at gun shows or for sales between private individuals.
Bloomberg, an independent, tested that support in the California congressional race, which because of state rules featured two Democrats head-to-head on Election Day.
His political committee, Independence USA PAC, put $3.3 million into defeating Baca and supporting Gloria Negrete McLeod, a state lawmaker more supportive of gun control, according to the Center for Responsive Politics. Baca had been endorsed by the NRA in the past.
Before he lost, Baca denounced Bloomberg's advertisements as "gutter politics at its worst" at a news conference.
The mayor's organization, which ran similar ads in other races in 2010, left no doubt of its goal.
"For a long time, the perception was, unless you voted the NRA's way, you would be defeated," New York City Deputy Mayor Howard Wolfson told Reuters. "The Baca race shows voting with the NRA can result in your defeat, and we hope members of Congress were watching."
The NRA had also made Obama's defeat a priority, telling members to go "all in" and warning that a second Obama term would threaten gun rights.
"If the NRA's money does not influence election outcomes, then the question becomes: why do candidates fear them?" asked the Brady Campaign to Prevent Gun Violence, a gun control group, in a statement after the election.
Ron Bonjean, a former Republican congressional aide, said gun control is still a risky issue for any politician. "The issue is so far down the priority list of Americans now," he said, citing the economy as voters' overriding concern.
Editing by Mary Milliken and Paul Simao