That's how he knows all about it. He can't imagine that an administration could function without a fulltime war-room putting out the day's talking points and searching for enemies to destroy. He knows this administrations doesn't use weasels like Ron Emmanuel et al, so it must be through Rush....
"Yeah! That's the ticket....Rush is the Kingpin in the Vast Right Wing Conspiracy those meanies are using to keep me from my birthright!!