The mess that is Afghanistan just got messier for Washington.

Abdullah’s withdrawal from the presidential runoff leaves Hamid Karzai in power but without legitimacy.

He’s widely perceived to have rigged the last election, and Abdullah took himself out, he says, because he couldn’t be assured that Kazai wouldn’t do it again.

And then they cancelled the election with only Karzai in it, citing security and cost reasons. But maybe they didn’t want to deal with the embarrassment of Karzai running unopposed, or the even deeper humiliation of a tiny turnout.

As a result, though, Karzai has become further delegitimized.

He was already in the soup. People in Afghanistan recognize that he’s corrupt. And Malalai Joya, the outspoken feminist who was booted from parliament, has been denouncing him for years now for surrounding himself with drug lords and warlords and war criminals. Even his own brother is involved in the drug trade.

In Afghanistan, Joya says, Karzai is seen, correctly, as a Washington stooge. And we’re seen there, correctly, as an occupying power.

We’ve been down this road before.

In Vietnam, the United States propped up one illegitimate leader after another, but that didn’t help the war effort at all. It only further alienated the people of Vietnam.

We’re seeing the same thing happening in Afghanistan right now.

Karzai is our guy in Kabul, but that’s about it. Many if not most people in Afghanistan disdain him. And the more he plays ball with Washington, the less support he has at home.

The United States can’t defeat an insurgency by backing an illegitimate government.

And the United States can’t defeat an insurgency when the American people are already opposed to the war.

Obama needs to realize all this, reverse course, and head for the exits, before he makes matters even worse.