No one vetted Palin before JMcC picked her. Apparently no one vetted her canned debate commentary either.
In a nutshell, the quote from Reagan she used at the end of the debate is from a little propaganda movie Ronnie did back in the 1960's hoping to snuff out Medicare before it could be created in law.
Here's the poster from Operation Coffee Cup:
The full details are here:
Raising the white flag of surrender to Medicare - Paul Krugman - Op-Ed Columnist - New York Times Blog