Defense Secretary Robert Gates urged Congress to repeal “Don’t ask, don’t tell” in the lame-duck session but was not optimistic of its chances.

“I would like to see the repeal of 'Don't ask, don't tell,' but I'm not sure what the prospects for that are,” Gates told a news conference in Australia, according to The Associated Press.

“Don’t ask, don’t tell,” the ban on openly gay members serving in the military, has been challenged by federal judges who question the constitutionality of the ban, but a full repeal in the courts could take years.

A legislative repeal, attached to the Defense Authorization Act, failed to generate enough support in the Senate shortly before the midterm elections. The prospects of any renewed legislative action diminish significantly once the 112th Congress begins in January, where Republicans will have control of the House and Democrats face a slimmer majority in the Senate.

The Pentagon is due to publish a working group report on Dec. 1, to provide guidance on the effect of a repeal of “Don’t ask, don’t tell” on the military. President Obama has said there is room in December or January for a legislative repeal, after the Pentagon’s report.