This is an interesting article in today's Charlotte Observer; he has no problem suggesting the main course was Bush en flambe. (Colbert is quoted more than Bush, more than the 3 or 4 paragraphs I'm allowed to re-print here, also an interesting list of the Carolinas connections to DC).
http://www.charlotte.com/mld/observer/news/local/14470145.htmAt press dinner, everyone a comic
President, impersonator share stage; Carolinas well represented WASHINGTON -- President Bush and Dubya impersonator Steve Bridges got the loudest laughs at the 92nd annual Washington Correspondents Dinner Saturday night. Standing side by side behind matching presidential seals, they joked about ... you name it: Bush's malapropisms, first lady Laura Bush's sex appeal, even Vice President Dick Cheney's hunting mishap.
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Start with Charleston-bred Stephen Colbert, the mock-conservative host of "The Colbert Report" (pronounced Coal-bear Re-pour) on Comedy Central.
As the evening's official entertainment, he drew blood with his satiric jabs at Bush, the White House press corps and Fox News -- home of Sean Hannity and Bill O'Reilly, the right-leaning pundits Colbert apes on his weeknight show.
The fake-news anchor even invoked a Carolinas university in one of his jokes.
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More, McCain and BJU in the link