Military training to apply the new law allowing gays to serve openly will begin in February and will move quickly, senior Pentagon leaders said Friday.
They said there is no intent to delay the law but would not guarantee full implementation of the repeal of the military's "don't ask, don't tell" policy this year.
The hedge on scheduling came despite assertions by President Obama in his State of the Union speech this week that the repeal of the 17-year-old ban will be finalized in 2011.
Speaking to Pentagon reporters, Gen. James Cartwright said he expects the military services to move expeditiously to train the bulk of their units and that a year for completion is "a good goal."
He added, "There's nothing that tells us that it's not reachable, but we have to allow for the fact that we may discover something between now and then."
Cartwright, vice chairman of the Joint Chiefs of Staff, said he expects the military services will know within the first month of training how well they are doing and how quickly they will be able to proceed.
He and Clifford Stanley, the defense undersecretary for personnel, said the services will have a lot of latitude to determine their training process and schedule.
Calling this a milestone event for the armed services, Defense Secretary Robert Gates in a memo Friday said a guiding principle is that "all personnel will be treated with respect."
"Harassment or unlawful discrimination of any member of the armed forces for any reason will not be tolerated," he said, adding that he wants the implementation done in a timely, comprehensive way.
The implementation plan will go to Gates next Friday, and training materials will be delivered to the services at the same time. Gates wants progress updates every two weeks.
Under the law passed and signed by the president late last month, final implementation will go into effect 60 days after the president and his senior defense advisers certify that lifting the ban won't hurt troops' ability to fight.
Military officials, speaking on condition of anonymity to discuss personnel matters, have said they expect to be able to train the bulk of the force over the next three months.
But Pentagon leaders have also cautioned that training the entire force will be difficult because troops are scattered around the world, and many are in various phases of deployment to war or heading home.
The training package will include slides, possibly a video, and a list of examples that describe how leaders can handle situations that arise.
Advocacy groups lauded the military's action.
"This is an historic day for the Defense Department and a new day for gays in the military," said Aaron Belkin, director of the Palm Center, a research institute at the University of California, Santa Barbara, which supports the repeal.
Cartwright and Stanley said that until the repeal is final, dismissals under the current gay ban could continue. They said no one has been approved for discharge for being openly gay since October when Gates put authority for signing off on dismissals in the hands of the three service secretaries.
According to Friday's memo, once the repeal is fully implemented service members in the process of being discharged solely under the provision of the gay ban will be returned to duty. All pending investigations under the ban will cease.