It’s fascinating that candidates are allowed to acknowledge contingencies when talking about the economy but not in the case of Iraq. Here’s Barack Obama’s response Maria Bartiromo on whether he would raise taxes:

Well, look, there’s no doubt that anything I do is going to be premised on what the economic situation is when I take office. I’m going to be sworn in in January, we don’t know what the economy’s going to look like at that point.

Sounds reasonable. Yet when his adviser Samantha Power said the same thing about Iraq—that Obama would have to evaluate the situation on the ground when he arrives in office—she was flayed alive.

There are differences, no doubt. Power used the phrase “best-case scenario” to refer to Obama’s plan for withdrawal. She also coupled it with her off-the-record-but-not “monster” comment. (If she hadn’t said that, the Iraq withdrawal exchange might never have made it overseas.) But given what could happen to the economy, perhaps Obama’s $30 billion stimulus package plan is a best-case scenario.

So, why is it OK to discuss hypotheticals with the economy but not with Iraq? Two reasons. For one thing, people know more about what’s happening in Iraq than they do about what’s happening to the economy, and therefore feel more qualified to challenge experts on the topic. But also, it’s that Democrats are politically tethered to withdrawal. Pulling out of Iraq has become an inflexible campaign platform. If conditions in Iraq were to improve (many suggest they are already improving), the Democratic candidates would have a hell of a time admitting it, since that would be seen as a victory for McCain. That’s why even hinting that conditions in Iraq could change—and that plans would then adjust—got Sam Power ousted.

It would be absurd for Obama’s opponents to drill him for saying he’d change his plan to meet current economic conditions. No more absurd, however, than the whole Power pile-on.