AFAIK, it started in 1993 on a small scale with President Bill Clinton protecting from federal prosecution the importation by Chinese of x-Soviet firearms for trans-shipment to Mexican buyers. I recall the name of one of the bundlers being in the papers at the time. This was for Clinton's personal gain initially, but it grew rapidly from there. He quickly put the whole government up for sale, i.e., Congress could do it too, and THAT green-lighting of rampant federal corruption was his real protection for sale of national security interests to the Chinese.
He got away with the gun-running and lesser stuff initially because he successfully blackmailed the national security establishment over something really awful they had done during the Carter administration.