Being anti-government does not make you a conservative
Just about the only thing in the ravings of the Arizona assassin that the Left have been able to seize on as being conservative is that he was "anti-government".
But, in their confused way, Leftists (particularly the more extreme ones) are often anti-government too. Most of the support for Julian Assange of Wikileaks fame, for instance, has come from the Left. And the far Left is certainly disgusted with the Obama administration.
And conservatives are not anti-government anyway. Unlike libertarians, they are strongly supportive of some government activities (defense etc.). They want limited government, not no government.