A cacophony of calls to change gun laws has emerged after last week's tragedy in Connecticut, and the National Rifle Association has kept quiet.

But no one expects silence from the NRA once President Obama or members of Congress make any move to change the laws.

For years, the well-known gun rights advocate and lobbying group has laid the ground work to ward off any move to change national gun policy, spending millions of dollars to kill laws that would make it tougher to buy or wield guns.

Enlisting celebrities such as Chuck Norris and the late Charlton Heston as spokesmen, the NRA is considered royalty in Washington, and is known to easily mobilize its 4 million members.

"The whole fire arms community is very powerful, because gun owners see their relationship to this democracy through the eyes of the gun issue," said Richard Feldman, a former NRA lobbyist and president of a gun rights group called the Independent Firearm Owners Association.

The NRA did not respond to requests for comment by Tuesday morning nor issued a press statement since the massacre of 20 school children and six adults at an elementary school in Newtown, Connecticut.

Related: NRA breaks its silence

This year, the NRA spent $17 million on federal elections. It's a considerable amount when compared to the size of the industry. Annual gun sales in the U.S. total about $3.5 billion, according to estimates from Wedbush Securities analyst Rommel Dionisio.

Compared to that, Goldman Sachs (GS)' corporate political action committee and employees spent a total of $7.5 million on candidates running in the November election. The investment bank raked in $29 billion last year.

"But Goldman Sachs doesn't have 4 million members who are very passionate, vocal and well-distributed from coast to coast," said Sheila Krumholz, executive director for the Center for Responsive Politics, a group that tracks political spending. "Certainly money is part of that, but the NRA is one of the most powerful lobbies in Washington, because they can draw on such a huge base."

The NRA didn't fare so well in the latest election -- only a handful of the candidates it supported won, according to the Center. But experts say the NRA is in strong shape to defend against any move to limit assault rifles like the one used in Friday's school shooting.

The NRA has flexed its muscles well in the past. It managed to push through new laws relaxing gun bans in national parks and Amtrak trains in 2009, a year when Democrats pledging stronger gun control laws controlled both Congress and the White House.

So far this year, the NRA and other groups that lobby Congress and the White House on gun rights have spent close to $4 million, according to the Center for Responsive Politics.

And while President Obama has renewed his commitment to reinstating a federal ban on assault weapons, he has shied away from taking on the gun lobby.

"President Obama did everything in his power to keep from making the gun issue the defining issue in the past campaign," Feldman said. "If Congress goes after the lawful ownership of guns, they'll deal with very difficult re-election campaigns in coming years."

But on Sunday, two days after the shooting, Obama said in a speech at Newtown: "If there is even one step we can take to save another child, or another parent, or another town, from the grief that has visited Tucson, and Aurora, and Oak Creek, and Newtown, and communities from Columbine to Blacksburg before that - then surely we have an obligation to try."

Democratic Sen. Dianne Feinstein of California on Sunday said she would introduce a bill next month to ban assault weapons and limit magazines to 10 rounds. Sen. Frank Lautenberg, a Democrat from New Jersey, also said he would reintroduce legislation to get rid of high capacity magazines.

Gun manufacturers have thrown their money and support to gun rights policy, through the NRA over the years. Sturm, Ruger & Company (RGR)donated more that $1.2 million to the NRA in April, after pledging to donate $1 for each new Ruger firearm sold between the 2011 and 2012.

Corporate sponsors involved with a campaign called "Friends of the NRA," include gun makers Winchester and Smith & Wesson (SWHC), guns and ammunition retailers Midway USA and Benelli, and outdoor gear suppliers Brunton Hunting, Hunter's Specialties and Legacy Quest and Boyt Harness Company, according to the NRA's website.