Ahmed Rashid in the New York Review of Books:
Pakistan's safe havens for the Afghan Taliban have been to a large extent responsible for their revival and growing dominance across Afghanistan and for the rising death toll among NATO forces. But the Taliban were not the major cause of the political crisis that enveloped Afghanistan after the August 20 presidential elections.
US officials told me in April 2008 that President Bush had been warned by his military commanders that Afghanistan was going from bad to worse. More troops and money were needed; reconstruction was at a standstill; pressure had to be put on Pakistan; the elections in April 2009 should be indefinitely postponed. Bush ignored all the advice except for asking the Afghans to postpone the elections until August.
He left everything else to his successor to sort out. When Obama took over in January, the crisis was much worse and Pakistan and Afghanistan immediately became his highest foreign policy priorities. Obama added 21,000 more troops, committed billions of dollars to rebuild Afghan security forces and speed up economic development, and sent hundreds of American civilian experts to help rebuild the country. He has attempted to make the anti-narcotics policy more effective and to involve neighboring countries in a regional settlement. It's an assertive and possibly productive new strategy, but the Obama administration has had neither the time nor the resources to implement it.
More here.