The NBAA website contains a useful primer on the Twelve-Five Standard Security Program. Here is an excerpt providing a concise history of the security protocol:

Belize Belize is the only Central American country that was not solely a Spanish colony, with Spain and Great Britain disputing rule over the territory in the 17th and 18th centuries. In 1854, it officially became the colony of British Honduras, and remained so until it achieved independence in 1981 and became Belize. (The independence process was inhibited by a border dispute with Guatemala, which continues toward a so-far unscheduled referendum in both states to determine whether to refer the conflict to the International Court of Justice at The Hague.)

What has become of the TSA's controversial Large Aircraft Security Program (LASP) for FAR Part 91 operators? The initial proposal met with such fierce resistance from the business aviation community that it was withdrawn for further revisions. A Notice of Proposed Rulemaking for a kinder, gentler LASP II was slated for release in the September 2012 time frame. But now, word has it that because of the presidential election cycle, the NPRM will be delayed until next year — perhaps as late as spring 2013.