I can't imagine why!
From TPM's Eric Kleefeld:
A new poll of Rep. Joe Wilson's (R-SC) district by Public Policy Polling (D) says that the controversial Congressman may have seriously landed himself in hot water through his "You lie!" outburst -- and is now trailing his Democratic opponent by one point.
Democratic candidate Rob Miller, who has received a ton of money from donors around the country since Wednesday night, now has 44%, to Wilson's 43%. The two both have 75% support among their own parties, but Miller leads among independents by 47%-39%. Only 29% of the total pool of respondents approved of Wilson's actions at the speech, compared to 62% who disapproved.
Wilson won re-election over Miller by 54%-46% in 2008, after having previously won his races with support of more than 60% or even over 80% of the electorate.[snip]
From the pollster's analysis: "In a matter of seconds Joe Wilson turned himself from a safe incumbent into one of the most vulnerable Republicans in the country for 2010."