Here’s a case where "leading from behind" should work for Barack Obama.

The new Post/ABC poll indicated that continuing support for the U.S. mission in Afghanistan is hard to find, with 60% of respondents saying they don't think the war is "worth fighting."  Obama's approval rating on his policy in Afghanistan is at 46%, back down to where it was last winter before American forces killed Osama bin Laden.

Is this a problem for Obama? Or is it good for him?

It seems to me that all of this winds up leaving Obama in the driver's seat. After all, his policy now is, in fact, to get out of Afghanistan. The political risks in such a policy aren't usually going to be about getting out a bit too slowly. That’s particularly true as long as casualties are dropping, which has been the case for a while now. The risk is that the the president's opponents will accuse him of selling out the mission, and then if something bad happens, they'll have ammunition to use against him. However, if there's a consensus forming in favor of withdrawal, then Obama is probably on very safe political ground following that consensus. 

What’s more, there isn’t even consensus among Republicans that we should stay in Afghanistan. As Spencer Ackerman notes, Republican presidential candidates Newt Gingrich and Rick Santorum are shifting to (qualified) dovishness on the war. Gingrich for the moment recommends pulling out and Santorum urges what Ackerman calls a "Go Big or Go Home" policy. Mitt Romney, for now, hasn't joined them. For now, Romney seems to be trying to thread the needle between bellicose words abou how weak Obama is and proposed policies which don’t seem to differ much from what Obama is doing. This may work within Republican primaries but is unlikely to move general election voters, who — as today’s poll confirms — are not in a warmongering mood.

The truth is that, barring high casualties, it's never very likely that foreign policy will have a strong effect on presidential elections. To the extent there might be an effect, it's far more likely that the president who ended the Iraq war and killed bin Laden will be helped, not hurt. But the current polling on Afghanistan probably gives Obama cover for doing what he wanted to do anyway, which is to continue to draw down the troops and end the war.