Preemptive Accusations of Hypocrisy

I thought this was a strange post from Megan McArdle:

What happens to the cottage industry among Democratic-leaning armchair economists grinding out analyses proving that Democratic presidents are, like, totally awesome for the economy? Presuming that we’re stuck–as seem very likely–in at least a couple of years of really grinding low-to-no growth, Obama is going to destroy their figures. Are we in for a resurgence of belief in exogenous growth factors?

To recap, historically economic performance has been better under Democratic presidents than under Republican ones. It seems to me that if you are a partisan of progressive economic policies, you’d have to be insane not to mention that fact. But Megan’s concern is that if future growth is so poor as to make it no longer be the case that Democratic presidents have seen better performance than Republican ones, that liberal pundits will hypocritically cease to believe that presidents impact the economy. This seems to me like a bridge we can cross when we come to it. Meanwhile, among the progressive pundits I read there’s been a great deal of concern that the Obama administration’s policies may lead to unsatisfactory growth results.

But to look at the specific data that I’ve seen most recently, here’s Larry Bartels’ work on the different fates of different income brackets under Democratic and Republican presidents:

I don’t see any reason to expect this pattern to break down. Average incomes actually declined over the course of the Bush administration, the worst performance of any president ever. So even if Barack Obama were to turn in a very disappointing pattern of zero income growth over the course of four or eight years, you’d simply see the level of both lines decline, not the relationship between them shift.

But we’ll see—if Obama turns out to be a really crappy president, my expectation is that I’ll say things like “wow, things went really poorly when Obama was president.”