By Jennifer Rizzo and Shirley Henry
Joint Chiefs Chairman Gen. Martin Dempsey said Wednesday he clearly understands a complete withdrawal of U.S. troops from Afghanistan by the end of 2014 - known as the "zero option" - is a "possibility" given Afghan President Hamid Karzai's current unwillingness to sign the security pact that would govern some troops remaining in his country beyond that time frame.
But Dempsey also said he has not been told to plan for such a withdrawal.
The United States is pushing for the agreement to be signed by the end of 2013, although Dempsey said the Pentagon could still figure out a way to leave a residual U.S. force behind if an agreement is signed by early summer of 2014.
"Nothing is irreversible," Dempsey said, referring to troops that would have been withdrawn from Afghanistan by then.
However, Dempsey warned that a delay would result in an "erosion of the coalition" because NATO countries engaged in Afghanistan could not necessarily wait as long for an agreement. A delay also would erode confidence among the Afghan security forces that U.S. and NATO troops are continuing to train and support.
U.S. Secretary of State John Kerry highlighted the concern for NATO allies in Brussels on Tuesday.
"There are over 50 nations who are engaged here through NATO in trying to help Afghanistan," Kerry said. "And those nations have budget cycles. Those nations have planning requirements. Those nations have equipment requirements. They have deployment requirements. And all of those things are best managed with planning."
The agreement has been endorsed by the Afghan council of tribal leaders, called the loya jirga, but Karzai said he won't sign it until after the country's elections in April and until certain conditions are met. These conditions include an end to U.S. raids on Afghan homes and the release of Afghan prisoners from the Guantanamo Bay detention center.
Washington has resisted such changes, saying Karzai's demands are new provisions added to a deal that was already reached.
Kerry, however, thinks the authority to sign the pact doesn't lie with Karzai alone.
"His minister of defense can sign it, the government can sign it, somebody can accept responsibility for this," Kerry said.
The security pact would be necessary to protect any residual force of U.S. troops in Afghanistan after 2014