Although President Obama did his best to put a positive spin on the review of the Afghanistan war released last week, the report itself offers scant hope that the United States can achieve its goals within an acceptable time frame and at an acceptable cost.

The president gamely said that U.S. strategy was ``on track'' and that ``considerable gains'' were being made against the Taliban and al Qaeda, and there is some evidence of that. But the report makes clear that the gains are fragile, the momentum reversible and the conditions going forward are challenging. In short, it's still dicey.

The reasons for the lingering doubts about what is turning out to be America's longest war are no mystery. A dysfunctional government led by an unreliable ally, President Hamid Karzai, remains an obstacle to progress. It is riddled with corruption, lacks a functioning judiciary and has little grassroots support among Afghans.

Absent a commitment to remain for years, which a war-weary American public would find unacceptable, the United States and its allies cannot fix what really ails Afghanistan.

In a sense, Mr. Obama confirmed as much, insisting that the United States would begin a ``responsible reduction'' of U.S. troops from Afghanistan in mid-2011, a message both to his domestic audience and to President Karzai that, yes, the United States is committed to a withdrawal even amid the uncertainty.

This is a message that Afghanistan's president needs to hear and digest, because the signals he's been getting from Washington have not been consistent. In Bob Woodward's recent book, Obama's Wars, he writes of a dinner inside the Beltway last May where Defense Secretary Robert Gates told Mr. Karzai, in the presence of others, ``We're not leaving Afghanistan prematurely . . . In fact, we're not ever leaving at all.''

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