This Andrew Sullivan guy is a liberal version of a Birther. He's been claiming that Sarah Palin's child Trig isn't really hers, and demands she show proof even though she isn't running for anything and even if she were it would have no legal significance.
And if you are interested, here is a conservative blog's response to your linked article...
Sullivan, who claims to care about national debt, begins by arguing, contrary to reality, that Obama’s massive $787 billion stimulus (actually, $862 billion) turned the economy around. He offers no proof other than the post hoc, ergo propter hoc fallacy familiar from basic economics. Sullivan also ignores the composition of the stimulus, which shoveled cash to cronies and bloated big states with their massive public sector obligations.
