SANTA CRUZ, Bolivia >> The Pentagon’s top leaders are warning that if Congress fails to repeal the ban on gays serving openly in the military, the courts may order changes that military leaders consider too fast or poorly thought-out.

The Pentagon is trying to make it easier for the Senate to consider lifting the ban in the current postelection session. Defense Secretary Robert Gates said Sunday he will release a study of the effects of repeal on Nov. 30, a day earlier than planned.

That could allow the Senate Armed Services Committee to hold hearings on the ban the same week.

The report on the impact of lifting the ban is meant as a guide for Congress as it considers what the Pentagon hopes will be a gradual and carefully calibrated change.

The Washington Post has reported that the study concludes the military can lift the ban with only minimal and isolated incidents of risk to the current war efforts.

“The timing and the legislative approach and so on, that is completely up to the Congress. All I know is if this law is going to change, it’s better to be changed by legislation rather than have it struck down by the courts,” Gates said.

Pentagon Press Secretary Geoff Morrell said later that Gates pushed his staff to deliver the report a day early in order “to ensure members of the Armed Services Committee are able to read and consider the complex, lengthy report before holding hearings with its authors and the Joint Chiefs of Staff.”

Gates spoke in Bolivia, where he is attending a regional defense conference.

The chairman of the Joint Chiefs of Staff said he supports Congress using its lame-duck session to end the ban known as “don’t ask, don’t tell.”

“The courts are very active on this. And my concern is that at some point in time the courts could change this law and in that not give us the right amount of time to implement it,” Mullen said on ABC’s “This Week.”

Mullen said he supports ending the ban because asking people to lie about themselves “goes counter to who we are as an institution.”