Reporting from Washington — Armed with a long-awaited Pentagon study that foresees little negative impact from gays serving openly in the military, President Obama and top Pentagon officials called Tuesday for the quick repeal of the "don't ask, don't tell" policy, which has ruled the military for 17 years.
But even with the findings of Tuesday's report, there was no indication that the Obama administration would be able to overcome fierce Republican objections in the few weeks left in this year's postelection congressional session.
Obama called on the Senate to act quickly so he could sign the repeal by the end of the year to "ensure that Americans who are willing to risk their lives for their country are treated fairly and equally."
At a news conference, Defense Secretary Robert M. Gates and Adm. Michael G. Mullen, chairman of the Joint Chiefs of Staff, said failure to act soon would increase the chances of the ban being overturned in the courts, which they called the worst possible scenario.
In October, a federal judge in Riverside ordered an immediate and permanent halt to the policy for all military personnel. The order has been on hold while the case is being appealed to the U.S. 9th Circuit Court of Appeals.
The study released Tuesday concludes that a repeal of "don't ask, don't tell" might cause some disruption at first but would not create widespread or long-lasting problems if the military provided proper training and took other steps to smooth the integration of homosexuals.
"We are convinced the U.S. military can make this change, even during this time of war," the Defense Department report concludes, noting that 70% of the tens of thousands of military personnel and family members surveyed predicted there would be "positive, mixed or no effect" from allowing gays and lesbians to serve openly.
Republicans, led by Sen. John McCain of Arizona, have mostly opposed overturning the law, saying Obama's call for an end to the ban is politically driven and could harm military readiness while the country is at war.
Opposition in Congress is likely to focus on divisions among the military's senior civilian and uniformed personnel about whether to overturn the law, especially during wartime. The Senate Armed Services Committee will hold hearings Thursday and Friday at which top Pentagon leaders are scheduled to testify.
Most Democrats support the repeal and one Republican, Sen. Susan Collins of Maine, has voted in favor of it in committee proceedings. Even McCain said in an interview in 2006 that he would seriously consider dropping the ban if the military leadership advocated the change.
Lawmakers who favor the ban are likely to seize on data in the study — completed by more than 115,000 troops and 44,200 military spouses — showing that military personnel in combat units, especially those in the Marines and Army, have greater concerns about serving with homosexuals than do military personnel overall.
At least 40% of combat troops raised some concerns. Among Marines, the smallest of the services and the most conservative, the figure approached 60%.
But the study's authors, Pentagon General Counsel Jeh Johnson and Army Gen. Carter F. Ham, told reporters that such worries were exaggerated and based on stereotypes about homosexuals.
They noted that most of those who had direct contact with a service member believed to be gay or lesbian encountered few problems. Almost all of them said their units were able to work together and only 8% said the units functioned poorly as a result.
Under the 1993 law, the Pentagon is required to remove service members found to be gay or admitting to being so. More than 14,000 service members have been discharged for those reasons.
Gates acknowledged that the chiefs of the Army, Navy, Air Force and Marines are more worried than he is that allowing gays and lesbians to serve openly could harm combat readiness at a time when there are nearly 100,000 troops in Afghanistan and tens of thousands in Iraq.
He said the military needed time to prepare for such a far-reaching change, even though the study did not call for major adjustments to housing or other personnel policies. He said a court ruling would give the Pentagon little time to prepare, and he issued an implicit warning to those in Congress who oppose repeal.
"Given the present circumstances, those that choose not to act legislatively are rolling the dice that this policy will not be abruptly overturned by the courts," Gates told reporters.
Gates said that even if Congress repealed the law, the military would not immediately lift the restrictions on gays serving in the armed services. Gates said the Pentagon would need time to prepare and train its personnel, especially those in combat units.
Under the legislation currently under consideration in the Senate, the repeal would not take effect until Obama and senior Pentagon leaders certified that it could be done without harming military readiness. Gates declined to say how long he thought it would take to reach that point.
In general, the Pentagon would not have to rewrite its regulations on housing, benefits or fraternization, the report says, though it calls for some changes.
The report recommends against creating separate bathrooms and living facilities for homosexual service members, arguing that to do so would create a "logistical nightmare" and would stigmatize gays.