The Arizona assassination attempt on Rep. Gabrielle Giffords has focused attention on U.S. gun laws, which are among the most permissive in the developed world. Here are some of the key federal and state laws:
* CONSTITUTION:: The Supreme Court in a key ruling in 2008 supported the right of individual Americans to own guns for self defense. Gun owners, represented by the powerful National Rifle Association, have jealously guarded this right and opposed any proposed law they see as diluting it.
* BRADY LAW: The so-called Brady law went into effect in 1994 requiring a criminal background check before a handgun could be sold to a buyer. Named after Jim Brady, the press secretary to then-President Ronald Reagan, who was seriously wounded in the assassination attempt on the president in 1981, it established a national instant criminal background check system.
The system keeps records on criminals and the mentally unfit so they can be denied guns. In 2008, after the Virginia Tech massacre by a disturbed student who should have been barred from purchasing a gun, a new law was passed offering funding to states to improve the records in the criminal background system, though many states including Arizona are still not up to date.
* ASSAULT WEAPONS BAN: For a decade until 2004, the U.S. banned civilians from owning certain types of assault weapons. This ban was allowed to expire during the administration of President George W. Bush. Police said the young man arrested in the Arizona shooting, Jared Lee Loughner, purchased a semi-automatic Glock pistol from a Tucson gun dealer in November. This has prompted some in Congress to call for the ban on assault weapons to be reinstated.