The absence of serious progress this year has sown new doubts, here and abroad, that Mr. Obama will be able to reach even the scaled-down goals he set for America’s mission in the time he laid out in his speech at West Point seven months ago. The result is that the fierce debate over whether the war is worth the cost — a debate that Mr. Obama did not want to join until the Taliban suffered some losses — is unwinding one summer earlier than he had hoped.

Mr. Obama has begun losing critical political figures and strategists who are increasingly vocal in arguing that the benefits of continuing on the current course for at least another year, and probably longer, are greatly outweighed by the escalating price…

All this has made it harder than ever for Mr. Obama to convince the Afghans and the Pakistanis that the West’s commitment is enduring. “Politically, the support is absolutely crumbling,” said David Gordon, a former top official on the National Intelligence Council and at the State Department who is now at the Eurasia Group. “You can’t hide that from the players in the region, and when they see it, it makes them hedge even more, preparing for the post-American era.”