Many newspapers, including key opinion formers, are questioning the wisdom of widespread gun ownership. Former President Bill Clinton and his wife Hilary have emerged as prominent supporters of tougher controls. The law State laws on ownership, carrying and use of firearms differ widely. There are various levels of checks depending on what kind of weapon you want. Click here to find out about recent legislation.
Some states allow the purchase of both rifles and handguns without any form of prior licence.
State laws often mirror the demographic of the population - large rural populations have retained a more relaxed attitude towards firearms than cities. But even before the Columbine killings, the debate had intensified - and nowhere more so than in Colorado. The National Rifle Association campaigned for months to persuade the state legislature to pass laws allowing the carrying of concealed weapons. Despite the killings, the NRA went ahead with its annual conference in Denver, albeit in a much more toned down form. Many members of his own Democratic Party then accused Mr Clinton of backing off from tougher measures after the Republicans, many of whom are backed by the NRA, gained control of Congress.