As National Review and others have reported, conspiracy theories of the nonsensical “birther” variety are not solely, or even mainly, a feature of the Right. The Democrat-media complex does not like to report the fact, but the Left is chock-a-block with conspiracy-kookery; notably, a very large number of Democrats believe that the Bush administration was complicit in 9/11. Media Matters has attempted to explain that fact away — but Alex Koppelman at Salon fills in the picture:
… the Birther and Truther poll responses are nearly mirror images of each other. 58 percent of Republicans in one poll said they believe President Obama was not born in the U.S., or that they don’t know whether he was; 54 percent of Democrats gave a similar response to the 9/11 Truther question.