The awkwardly worded (and bafflingly punctuated) Second Amendment to the U.S. Constitution says the following: "A well regulated militia, being necessary to the security of a free state, the right of the people to keep and bear arms, shall not be infringed."
The interpretation of these 27 words ranks among the prickliest political issues in American history. Perhaps that explains why gun rights lingered in a legal fog for nearly 200 years before the U.S. Supreme Court affirmed the right to keep a gun in the home for self-defense [sources: 554 U.S. 570; Liptak; Myer ; The New York Times]. Before diving into that ruling, however, it is worth examining how Congress and the states have grappled with the issue.
States enjoy a wider authority than Congress to create laws, particularly laws related to exercising their policing power [source: Myer]. In the 1886 case Presser v. Illinois, the U.S. Supreme Court upheld states' latitude with respect to gun regulation, ruling that Second Amendment restrictions applied only to Congress and not to states [source: 116 U.S. 252].
Constitutionally speaking, Congress requires specific authority to act, and only defines criminal law with respect to federal property, crimes crossing state lines and matters of national concern such as interstate kidnapping. Consequently, many federal laws derive from its other powers. For example, the federal ban on felony gun possession flows from Congress's constitutional authority over interstate commerce under Article I, Section 8, which is why it is defined in such commercial terms [sources: GCA; Myer, 18 U.S.C. § 922]:
It shall be unlawful for any [such person] ... to ship or transport in interstate or foreign commerce, or possess in or affecting commerce, any firearm or ammunition; or to receive any firearm or ammunition which has been shipped or transported in interstate or foreign commerce.
Although states can write their own gun laws, they cannot violate the federal ban, because it derives from Congress's constitutionally granted powers. If that sounds like a technicality, it is, but it's far from the first time Congress has relied on it -- or its power over taxation -- to regulate firearms. As far back as 1915 and 1927, Congress passed laws limiting mail-order guns to close a loophole that enabled people to circumvent state laws. This early legislation set important precedents by largely blocking private citizens from engaging in the interstate gun trade and by establishing a dealer category subject to its own regulations [source: Zimring].
Those models would pave the way for Congress to establish and regulate licensed dealers -- and set the stage for bans on felon gun ownership.