Noting that Senate Republicans are refusing to extend expiring tax provisions now after having done so happily for years, Steve Benen wonders:

It's unpleasant to think about, and I really hope it's not true, but it may be time for a discussion about whether GOP lawmakers are trying to deliberately sabotage the economy to help their midterm election strategy. After all, these same Republicans have supported deficit-financed tax-extenders before -- there's no credible reason to change course now.

It's clear that the Republican Party has changed its positions in ways that are hard to explain without understanding that they once were in power and are no longer. The party fervently embraced the logic of Keynesian stimulus in 2001, when the underlying rationale was very weak, and fervently opposes it now when the underlying rationale is quite strong. If you were a principled opponent of Keynesian economic theory, you ought to have been more opposed to stimulus in 2001 than now, but very few Republicans were. Ezra Klein has another example today, of Republicans who favored an airline bailout in 2001. Most Republicans also supported a financial bailout in 2008. They just oppose bailouts when Democrats hold power.

Still, I think you have to be careful about making assumptions about motive like this. Establishing motive is always very hard to prove. What's more, the notion of deliberate sabotage presumes a conscious awareness that doesn't square with human psychology as I understand it. People are extraordinarily deft at making their principles -- not just their stated principles, but their actual principles -- comport with their interests. The old Upton Sinclair quote -- "It is difficult to make a man understand something when his salary depends upon him not understanding it" -- has a lot of wisdom to it.

I don't think many Republicans are actually trying to stop legislation that might help the economy recover because they know that a slow economy is their best route to regaining power. I think that when they're in power, consequences like an economic slowdown or a collapsing industry seem very dire, and policies to prevent this are going to sound compelling. When you're out of power, arguments against such policies are going to sound more compelling.

I'm not excusing their behavior. You can resist that kind of mental trap -- it just takes a lot of intellectual discipline and integrity. I don't think you're going to find a great deal of that sort of intellectual discipline and integrity among high-level politicians.