WASHINGTON - The Connecticut school shootings are likely to change the tone and perhaps the outcome of Congress' debate over gun control and other efforts to curb violence.

But don't look for big changes in those laws.

The Friday murder of 26 people, including 20 children, at Sandy Hook Elementary School has shaken lawmakers like few events in recent years.

On Capitol Hill Monday, some Democrats called for quick action on gun control, including Sen. Patty Murray and Rep. Rick Larsen, veteran Washington state Democrats who said it's time to ban assault weapons.

"No single law can prevent the action of a madman, but that is no excuse not to take action," Larsen said.

And Murray said "there is no question" Congress needs to act to limit the weapons.

"I have repeatedly voted for an assault weapons ban and will do so again as soon as we can get a bill to the Senate floor," she said.

Republican Rep. Cathy McMorris Rodgers of Washington state, who ranks fourth in House leadership, said that Americans and members of Congress alike "will come together ... to examine existing laws, study what is needed to make our schools and neighborhoods safe, and explore what can be done to ensure people have the mental health evaluation and treatment they need."

But history shows that shocks like this often result in an incremental change, but little more, as fierce lobbying and political concerns become paramount.

The drawbacks are mired in the kind of politics that has stifled action on controversial measures for years. The nation remains divided over how or whether to regulate firearms, and the gun lobby remains one of the Capitol's most powerful.

The National Rifle Association alone spent more than 10 times as much as gun-control groups on lobbying last year and in the first nine months of this year, according to data compiled by the nonpartisan Center for Responsive Politics.

The center found that last year was the most active election cycle in a dozen years for gun interest groups, as they gave $3 million to candidates, 96 percent of them Republicans, through mid-October.

Gun-control groups barely registered, giving only $4,000, all to Democrats.

The gun lobby was unrelenting Monday.

Eric Pratt, spokesman for Gun Owners of America, said if there's to be a discussion on gun legislation it "should lead to a greater ability to protect one's self ... "Sadly, they (gun-control advocates) will try to exploit this to make people less safe."

Some Republicans agreed.

Said Rep. Louie Gohmert, R-Texas: "I wish to God she (the Sandy Hook principal) had had an M-4 (rifle) in her office," so she could have taken it out and "takes his head off before he can kill those precious kids."

But gun control advocates had new hope on Monday.

Many Democrats, including President Barack Obama, who for years have been reluctant to speak out for tougher gun laws, aren't holding back.

And the Republican Party, trying hard to reposition itself after setbacks in last month's election, could be more sympathetic.

"I actually think things could change. The terrible nature of this shooting has the potential to transform the national debate," said Darrell West, vice president and director of governance studies at Washington's Brookings Institution.

Among those urging quick action was Sen. Dianne Feinstein, D-Calif., architect of the 1994 assault weapons ban. That ban expired in 2004, and Feinstein plans to mount a new effort.

Also pushing will be Rep. Carolyn McCarthy, D-N.Y., whose husband was killed during a mass shooting on the Long Island Railroad in 1993. She urged strengthening of background checks.

Lawmakers also renewed their pleas to tone down media violence.

For years, Sen. Joseph Lieberman, a Connecticut Independent, and his allies have called attention at this time of year to entertainment violence. In the wake of the Connecticut tragedy, Lieberman wants a national commission to study the matter.

One of the last major pushes for gun control came in 1999, one month after the nation was stunned by the shootings at Columbine High School in Colorado. As part of a juvenile justice bill, Democrats pushed a plan to require background checks at gun shows and pawn shops. The vote in the Senate was a 50-50 tie, with Vice President Al Gore breaking the tie and allowing the change to pass.

The vote became political mythology, that Gore's decision cost him valuable votes in his 2000 presidential bid, chilling gun-control talk by future Democratic White House hopefuls.

Reach ROB HOTAKAINEN at rhotakainen@mcclatchydc.com.