"According to Sarah Brady, had a background check been conducted on Hinckley, it could have detected some, or all, of this important criminal and mental health history.[6]

Sarah Brady, Jim's wife, became active in the gun control movement a few years after the shooting. She joined the Board of Handgun Control, Inc. (HCI) in 1985 and later became its Chair in 1989. Two years later, she became Chair of the Center to Prevent Handgun Violence, HCI's 501(c)(3) sister organization.

On February 4, 1987, the Brady Act was introduced in the U.S. Congress for the first time. Sarah Brady and HCI made the passage of the bill their top legislative priority.[7] In a 1991 editorial, President Reagan opined that the Brady Act would provide a crucial "enforcement mechanism" to end the "honor system" of the 1968 Gun Control Act and "can't help but stop thousands of illegal handgun purchases."[8]"

http://en.wikipedia.org/wiki/Brady_Handgun_Violence_Prevention_Act