But underlying the tensions, according to Mr. Saleh and Afghan and Western officials, was something more profound: That Mr. Karzai had lost faith in the Americans and NATO to prevail in Afghanistan.

For that reason, Mr. Saleh and other officials said, Mr. Karzai has been pressing to strike his own deal with the Taliban and the country’s archrival, Pakistan, the Taliban’s longtime supporter. According to a former senior Afghan official, Mr. Karzai’s maneuverings involve secret negotiations with the Taliban outside the purview of American and NATO officials.

“The president has lost his confidence in the capability of either the coalition or his own government to protect this country,” Mr. Saleh said in an interview at his home. “President Karzai has never announced that NATO will lose, but the way that he does not proudly own the campaign shows that he doesn’t trust it is working.”…

“Karzai told me that he can’t trust the Americans to fix the situation here,” said a Western diplomat in Kabul, who spoke on condition of anonymity. “He believes they stole his legitimacy during the elections last year. And then they said publicly that they were going to leave.”