By Daniel Trotta

NEW YORK (Reuters) - Once again there has been a mass shooting in the United States, this time in a Nebraska shopping mall. Once again there is no national outcry for gun control.

A 19-year-old man shot and killed eight people and then himself in Omaha, Nebraska, on Wednesday with a semi-automatic AK-47 that police say he stole from his stepfather.

Leading presidential candidates for the November 2008 U.S. election issued statements expressing sorrow and support for the victims. None called for tighter gun laws, which are traditionally left to state and local authorities.

The crime revived memories of a massacre in April at Virginia Tech university, where a student killed 32 people.

There has been a string of such shooting sprees in recent years, but little resonance among national politicians.

The right to bear arms is fiercely defended as a U.S. constitutional right by large numbers of collectors, hunters and advocates of home security, cherished the way civil libertarians champion the right to free speech.

Yet the issue is controversial enough to draw in the Supreme Court, which said last month it would review an appeals court ruling that struck down a 31-year-old ban on private possession of handguns in Washington, D.C.

"Although people who favor increased gun control in the United States are a substantial majority, those who oppose it are far more intense in their opposition and far more likely to vote on the basis of that issue alone," said Bill Galston, senior fellow at the Washington-based Brookings Institution.

He cited the 1994 elections when the Democrats lost control of both houses of Congress. Some political analysts attributed the rout to backlash against a Democratic-led ban on assault weapons. That law was allowed to expire 10 years later.

"I might want to qualify that judgment, but the fact that it's widely believed and that there is some basis for it is enough to determine political behavior," Galston said.

GUN LOBBY

A Pennsylvania state representative who last month helped defeat a proposal to limit hand gun purchases to one per person per month said he would support tougher sentencing laws for people who acquire and use illegal guns, but that law-abiding citizens should not have their rights infringed.

"I received thousands of e-mails with some of these gun control measures. Once again, it's the right to bear arms and many of our citizens don't want that right taken away," said Ron Marsico, chairman of the state House Judiciary Committee and a Republican.

Besides, he said, no law may have prevented the Omaha tragedy.

Paul Helmke, president of the Brady Campaign to Prevent Gun Violence, disagrees. He said European countries have enacted effective gun control laws and that U.S. politicians are cowed by the gun lobby as exemplified by the National Rifle Association.

"There is the mythology advanced by the gun lobby of the Wild West and the individual frontiersman single-handedly holding off the British and the Indians and the bears simultaneously," said Helmke.

"They've got politicians nervous about anything that's even got the word gun in it."