(CNN) -- In 1981, James Brady was shot in the head and gravely wounded in a shooting that also wounded President Reagan -- despite their both being surrounded by plenty of extremely well-trained "good guys with guns." At that time, federal law set conditions, such as a felony conviction or being involuntarily hospitalized for a mental illness, that prohibited a person from possessing firearms. The 1968 Gun Control Act had established record-keeping requirements and regulated interstate transactions of firearms, but there was no federal law requiring proof from a prospective buyer that he or she was not prohibited from possessing firearms.
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Daniel Webster: In 1981, when James Brady was shot, buying guns relied on "honor system"
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He says you only had to sign form saying law didn't prohibit you from owning firearms
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Brady Law helped fulfill goal of Gun Control Act, to keep guns from dangerous people, he says
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Webster: Its effect on public safety unclear, but background checks help
Because some states had background check requirements in place before the @placeholder, one way to estimate the policy's effects is to contrast changes in homicide trends in these states at the time the law was implemented with changes over the same period in states newly implementing background checks for sales by licensed gun dealers.