Knowing who Mr. Reagan's assistant executive officer was, it would not surprise me that a piece of paper was slipped in-between others and Mr. Reagan signed said authorization without his knowledge.
I'm just sayin'...
Keep in mind, that when Mr. Reagan was shot due to an assassination attempt - the Presidential limousine on its way to the hospital, the Secret Service completely familiar with the streets of Washington DC got "lost" for quite some time. The ambulance carrying James Brady, arriving to the assassination scene 5 mins after the Presidential limousine left with a wounded Ronald Reagan inside, arrived at the hospital
before the Presidential limousine. When Mr. Reagan found this information out, his relationship with his co-executive was never the same.
...and least we forget that GHW Bush and John Henkley Sr, the father of "crazed for Jody Foster" John Henkley Jr, were friends.
The two families lived close to each other. They knew each other socially and financially. When the Hinkley oil company started to fail in the sixties, Bush's Zapata Oil financially bailed out Hinkley's company. It went from being Vanderbilt Oil to Vanderbilt Energy or Vanderbilt Resources in the 60s after Bush intervened.
