WASHINGTON - Although discussions of US gun control are slowly gearing up after the Colorado mass shooting, experts say any real and robust debate could fizzle out before it really begins.

James Holmes was arrested after allegedly entering a theater and opening fire on a crowd of moviegoers, killing 12 and wounding 59 others. The gunman supposedly used semi-automatic weapons and more than 6,000 pounds of ammunition he bought online.

While the tragedy has to some extent rekindled the gun control debate, any major discussion of gun control so far remains unlikely, analysts said. The situation mirrors other times in recent years when mass shootings prompted gun control debates that eventually petered out.

"It doesn't look like the Colorado shootings will galvanize the gun control issue," said Darrell M. West, vice president and director of governance studies at the Brookings Institution.

"The National Rifle Association has a solid lock on the gun issue and effectively is preventing any serious discussion of gun violence. Americans don't like to connect our gun policies on assault weapons with violent crime and it doesn't look like that is going to change any time soon," he said.

Indeed, the debate has come and gone more than once over the last decade, and tends to emerge after such incidents as the recent Colorado massacre.

Moreover, the brutal attack has failed to drastically change American attitudes. According to a Pew Research Center poll taken earlier this month, 47 percent of Americans say gun control is a priority, while 46 percent say protecting gun owners' rights is more important.

The poll marked little change from an April study that found 45 percent of Americans thought gun control took priority and that 49 percent favored gun rights.

New York Mayor Michael Bloomberg wrote in an editorial last week that lawmakers' reluctance to vote for stricter gun legislation stems from fear of the National Rifle Association, but argued that the group's influence may be exaggerated.

The article cited Daniel Webster, co-director of the Center for Gun Policy and Research at the Johns Hopkins Bloomberg School of Public Health in Baltimore, who said that "Democrats have decided, I think wrongly politically and morally, that it's only an issue they can lose on."

Republicans typically oppose gun control legislation. New Jersey Senator Frank Lautenberg and New York Representative Carolyn McCarthy, both Democrats, on Monday introduced a bill that would ban ammunition buyers from purchasing unlimited amounts online or via mail. It would also require dealers to report to the government the sale of large quantities of ammunition.

"It's time to close the loophole that's allowing killers - deranged, insane - and even terrorists to buy ammunition online," Lautenberg said Monday.

But they unveiled the bill in New York, a state friendly to gun control, whereas many other Democrats will not touch the issue, viewing it as political suicide.

The announcement came on the heels of Sunday's statement by Supreme Court Justice Antonin Scalia, who said the Second Amendment of the Constitution leaves room for possible gun control laws.

The conservative justice told Fox News on Sunday that the 2008 case District of Columbia vs Heller found that the question will have to be decided in future cases.

Defenders of gun laws maintain that banning firearms leaves law-abiding citizens at the mercy of criminals. Tighter gun laws are unlikely to thwart criminals, they say, which leaves residents and business owners unable to defend themselves in the case of robbery or home invasion, for example.

On Wednesday, President Barack Obama spoke of possible tweaks to gun laws during a speech at the National Urban League, although he did not lay out any detailed plans.

He said that while he believed Americans had a right to own firearms, assault rifles are more appropriate for armed conflicts between nations than for domestic ownership.

Dan Gross, president of the Brady Campaign,an anti-gun lobby, called for more discussions "about the things we can do to prevent violence without preventing law-abiding citizens from safely and legally owning guns."

Gross on Friday called for "a respectful conversation" with a belief in the Second Amendment right to bear arms as well as a conversation that focuses on "what we can do to save lives."

Still, the organization called on Obama to hammer out something more specific.

"We applaud President Obama for speaking up in favor of sensible regulations that are consistent with his expressed belief in the Second Amendment," Gross said. "But we cannot be satisfied. The president said very similar things in his last campaign. A speech is not a plan."