Background checks have been in place for a number of years. There have been amendments made over the years to the way in which background checks are done. For example, they did not involve a tax compliance check at the very beginning, and they now do. I'm not sure if there was always a check about bankruptcy; that has been added. But the checks themselves have been conducted since at least the early 1960s, some form of background check.
On June 17th, 2008. See this statement in context.