The US military is rapidly expanding its aerial and Central Asian supply routes to the war in Afghanistan, fearing that Pakistan could cut off the main means of providing American and Nato forces with fuel, food and equipment.
Although Pakistan has not explicitly threatened to sever the supply lines, Pentagon officials said they are concerned the routes could be endangered by the deterioration of US-Pakistan relations, partly fed by ill will from the cross-border raid that killed Osama bin Laden.
Memories are fresh of Pakistan's temporary closure of a major crossing into Afghanistan in September, resulting in a logjam of hundreds of supply trucks and fuel tankers, dozens of which were destroyed in attacks by insurgents. While reducing the shipment of cargo through Pakistan would address a strategic weakness that US military officials have long considered an Achilles' heel, shifting supply lines elsewhere would substantially increase the cost of the war and make the United States more dependent on authoritarian countries in Central Asia.
A senior US defence official said the military wants to keep using Pakistan, which offers the most direct and the cheapest routes to Afghanistan. But the Pentagon also wants the ability to bypass the country if necessary.
"It's either Central Asia or Pakistan - those are the two choices. We'd like to have both," the defense official said, speaking on the condition of anonymity to avoid alienating Pakistan. "We'd like to have a balance between them, and not be dependent on either one, but always have the possibility of switching."
US military officials said they had emergency backup plans in case the Pakistan routes became unavailable.
"We will be on time, all the time," said Vice Adm. Mark Harnitchek, deputy commander of the US Transportation Command, which oversees the movement of supplies and equipment.
In such an event, however, the military would have to deliver the bulk of its cargo by air, a method that might not be sustainable; it costs up to 10 times as much as shipping via Pakistan.
"We'd have to be a little bit more mindful of what we put in the pipe," Harnitchek said.
(In Exclusive Partnership with The Washington Post)