The service chiefs wanted to have more than a year to implement the new policy, citing the need to train the force and prepare it for “open service,” according to a source close to the matter.

Marine Commandant Gen. Jim Amos, for example, may demand that physical modifications be made to accommodate concerns among some Marines about showering with other Marines who are serving openly. All of this could take time.

Amos may have backing on Capitol Hill, where Sen. Jim Webb (D-Va.), a former Marine, has been pushing the Pentagon to phase in any new policy. Webb said in a statement last week that Defense Secretary Robert Gates confirmed to him that implementation would be “sequenced in order to protect small unit cohesion.”

“We have not determined the specific methodology that would be used should this legislation pass, but I can assure you that the specific concerns that you raise will be foremost in my mind as we develop an implementation plan,” Gates told Webb in a Dec. 17 letter. “Further, the chairman of the Joint Chiefs of Staff and I remain committed to work closely with the Service Chiefs and the Combatant Commanders in developing this process.”

The Palm Center says repeal implementation should be swift and decisive, in a statement released on Saturday:

"Today, the Palm Center salutes the U.S. Senate for this courageous vote, which will improve national security and allow gay and lesbian troops to be treated with the same dignity as their straight counterparts. This is a historic day for the military and for the American tradition of civil rights, but this process does not end here. We expect the Pentagon to shortly announce its demand for a lengthy period of training and education to prepare the troops for open gay service, possibly lasting though much of 2011, before repeal of 'don't ask, don't tell' can be certified.

The Palm Center will imminently release a study showing that this demand is not based on actual military needs. In fact, the Pentagon has the capacity to train the forces immediately, within a matter of weeks. The RAND Corporation's research has found that the way to minimize any disruption from the implementation of open gay service is to proceed quickly and with strong leadership. Only three steps are needed to assure a smooth and quick transition to open gay service: an immediate executive order from President Obama suspending all discharges; a few weeks to put the new regulations in place; and following this, immediate certification to end ‘don't ask, don't tell.'"

The NYT has some further guidance:

“There will certainly be pressure to get it done in 2011,” one defense official said, indicating that repeal will be a relatively slow but not years-long process.

Phasing in the repeal by service branch, with some parts of the military affected before others, was “highly unlikely,” said the official, who asked for anonymity to talk more freely about internal deliberations at the Pentagon.

Under the terms of the legislation that passed the Senate on Saturday and the House earlier last week, the Defense Department will not carry out the repeal until Defense Secretary Robert M. Gates , Mr. Obama and Adm. Mike Mullen, the chairman of the Joint Chiefs of Staff, “certify” that the military is ready to make the change. After that, the legislation requires a 60-day period before the change takes place.

Gay rights advocates said Sunday that repeal should be carried out as quickly as possible, preferably in the first quarter of next year.

Mr. Gates has acknowledged that the president will be watching closely “to ensure that we don’t dawdle or try to slow-roll this” and that Mr. Obama expects the military to prepare “as quickly as we properly and comprehensively could.”