America's latest mass shooting, which left ten people dead in Roseburg, Oregon, followed the familiar pattern of a troubled young man murdering innocent people apparently at random. Chris Harper Mercer was an isolated, fragile 26-year-old who shared a small, one-bedroom apartment with his mother. He had developed an online enthusiasm for guns and violence, including an interest in the Provisional IRA. Despite his idiosyncrasies, however, Mercer was a typical perpetrator in what has become, as President Barack Obama observed, a routine element of American life.
It is the routine quality of these killings that moved the president to one of his rare displays of anger in the White House, as he declared that it was no longer enough to condemn the murderer and pray for his victims. "It does not capture the heartache and grief and anger that we should feel. And it does nothing to prevent this carnage from being inflicted someplace else in America - next week, or a couple of months from now," he said.
Mr Obama has identified lack of progress towards gun control as the most frustrating failure of his presidency and there is little hope that the Republican-dominated Congress will approve any new restrictions before he leaves office in January 2017. This failure to act leaves Congress at odds with most Americans, most of whom favour stricter gun laws, with nine out of 10 backing a federal law imposing mandatory background checks on anyone wishing to buy a gun.
More than 10,000 Americans are killed every year by gun violence, and there are as many guns in the United States as there are people. Terrorism, by contrast, has killed only a handful of Americans since the 9/11 attacks in 2001. Yet, as Mr Obama pointed out, "we spend over a trillion dollars, and pass countless laws, and devote entire agencies to preventing terrorist attacks". Meanwhile, America's politicians, cowed into silence by the noisy, well-funded and highly organised gun rights lobby, do nothing to stop further, preventable massacres.