"What colored State's thinking was the impact that the drone operations were having on public opinion and its constraint on the evolution of a civilian government," said a former senior State Department official, who asked not to be identified as discussing a classified program. "The continued attacks probably give motivation to those who would fight us."
Shamila Chaudhary, who was Pakistan director in the National Security Council until July, said U.S. counter-terrorism operations were "one reason, though not the only reason, that the U.S.-Pakistan relationship has disintegrated. Until the conflicts over that policy are resolved, the two countries will continue to go from crisis to crisis."
CIA officials argue that the drones have helped save American lives by eliminating militants who have engaged in cross-border attacks or are supplying bomb-making networks. In some cases, they say, Al Qaeda leaders were killed in airstrikes on groups of militants, although their presence was not discovered until later.
There is no way to independently assess the accuracy or effectiveness of the strikes. Since they are classified, the Obama administration refuses to release details about them and Pakistan has barred access to the tribal areas by Western journalists or humanitarian agencies, including the International Committee of the Red Cross.
According to Long War Journal, a website that tracks the attacks through Pakistani news reports, the CIA launched 64 drone missile attacks in Pakistan this year, the last on Nov. 16. That compares with 114 last year and 53 in 2009. The agency launched 46 during the Bush administration, mostly in 2008.
The death toll is unclear. The New America Foundation, a think tank in Washington, estimates that the CIA drones have killed at least 1,717 people, including 1,424 militants. Other estimates run considerably higher.
John Brennan, Obama's chief counter-terrorism advisor, said this summer that there "hasn't been a single collateral death because of the exceptional proficiency and precision of the capabilities we've been able to develop."
When human rights groups and others challenged that assertion, citing numerous Pakistani accounts of civilian casualties, Brennan clarified his comments to say there were no civilian deaths that the administration had confirmed. U.S. officials later acknowledged a few civilian deaths this year.
The pause in the drone war comes after steadily worsening relations between Washington and Islamabad.
In January, the arrest of Raymond Davis, a CIA contractor who shot and killed two men in Lahore, stirred up anti-American sentiment. The raid by a CIA-led Navy SEAL team that killed Bin Laden enraged many in Pakistan's military. The mistaken attack Nov. 26, which killed the 24 soldiers, caused a near rupture in relations.
After the raid, Islamabad ordered the United States to vacate Shamsi air base in southwest Pakistan, which the CIA had used to stage lethal drone flights. U.S. officials say the agency now flies drones into Pakistan from bases in Afghanistan.