For the sake of the Aurora threads, take your gun control discussion here.

ANOTHER day in America, and another mass shooting. It's amazing how a 24-year-old wielding an assortment of firearms can in a few senseless moments render impotent the most powerful political office in the world.

And that's basically because such atrocities in the US remain ''protected'' by an archaic 18th century constitutional provision that was essentially a precaution against federal interests hijacking the new republic.

Could America's founding fathers, with their unwieldy muskets and shot and little pouches of gunpowder, have possibly envisaged how their second amendment in the nation's Bill of Rights - that 27-word clause giving Americans ''the right to bear arms'' - could have become the bedrock for laws that made it possible for James Holmes to buy two pistols, a semi-automatic rifle and a shotgun since May?

On Friday, as the world was focusing on the shattered Colorado town of Aurora, Barack Obama demurred on the issue of gun control: ''There are going to be other days for politics … This, I think, is a day for prayer and reflection,'' he told reporters. And yesterday he stuck almost exclusively to words of condolence and sympathy in his weekly radio address from the White House that included the somewhat ambiguous line: ''We will take every step possible to ensure the safety of all our people.''

The pattern of response to such slayings has become all too familiar: overwhelming grief and dismay, then angst and anger and, finally, the promise of tougher gun laws. And then, the predictable push-back by the gun lobby, with its reprising of the old ''guns don't kill people, people kill people'' line and, ultimately, political deadlock.

It happened 13 years ago after Columbine, barely 30 kilometres from the scene of Friday's atrocity; after the 2007 Virginia Tech shootings (America's worst, in which 33 died); and after a deranged young man murdered six people in the car park of a Tucson shopping mall when targeting US congresswoman Gabrielle Giffords.

What seems to outsiders a national blind spot, is a fiercely contested right and in recent years US states have passed more laws relaxing gun controls than they have to tighten them. Meanwhile, courts nationwide are regularly called upon to defy legislators and declare reforms an infringement of Second Amendment rights.

This, despite the widely publicised statistics: every day, 86 people die from guns in America, as tallied by the Brady Campaign to Prevent Gun Violence, named after the White House press secretary who took a bullet, literally, for the president, Ronald Reagan, 30 years ago. What's more, there have been 50 mass shootings in America in the 18 months since Tucson.

Yesterday, gun supporters were already drawing on the notion that an armed and quick-thinking cinema-goer might have been able to round on the assailant and prevent many of the deaths, which has always been a core justification for ''conceal and carry'' laws in several states, including Colorado. (The release last week of an in-store video of an elderly Florida man pulling a gun on would-be armed robbers in an internet cafe was manna from heaven for the gun lobby.)

A great stumbling block is Americans' faith in their constitution. They just don't like meddling with it.

And no better illustration of the marked differences between Australians and our American cousins is the way in which John Howard, a conservative, was able to forge a political coalition in favour of tougher gun controls in the aftermath of the Port Arthur massacre.

Doubtless, there will be a crescendo calling for tougher laws, as predictable as all the lines in this modern American pantomime, and already some political figures are playing their roles. The former Democratic governor of Pennsylvania, Ed Rendell, for one, hit out at Congress's failure to reauthorise a federal ban on assault weapons, describing it as an ''act of cowardice'', while New York mayor Michael Bloomberg took aim at both Obama and his Republican challenger Mitt Romney.

''Soothing words are nice,'' Bloomberg said. ''But maybe it's time the two people who want to be president of the United States stand up and tell us what they're going to do about it, because this is obviously a problem across the country.''

But Bloomberg's constituency is one of the country's most liberal, and Rendell no longer has political ''skin in the game'', to adapt an American phrase. Memories of election loser Al Gore's advocacy for tighter gun controls still resonate in Washington, and less than four months from polling day neither Obama or Romney will be keen to incite the wrath of the 4-million-member strong National Rifle Association.

Responding to a 2010 court ruling that overturned Chicago's 28-year handgun ban, an NRA executive made clear the association's true target. ''We are drawing a line in the sand against more gun bans,'' he said. ''And we will fight back against politicians who try to ban our guns and ammo.

''Victory is when law-abiding men and women can get up, go out and buy and own a firearm,'' he added.