Elated by a major court victory, US gay-rights activists are stepping up pressure on Congress to repeal the military's "don't ask, don't tell" policy this month.
They want to avoid potentially lengthy appeals and fear their chances for a legislative fix will fade after election day.
The House voted in May to repeal the 17-year-old policy banning openly gay service members.
Many majority Democrats in the Senate want to take up the matter in the remaining four weeks before the pre-election recess, but face opposition from Republican leaders.
National gay-rights groups, fearing possible Democratic losses on November 2, urged their supporters to flood senators' offices with phone calls and e-mails asking that the Senate vote on the measure during the week of September 20.
"If we don't speak up now, our window for repeal could close," said Joe Solmonese, president of the Human Rights Campaign.
Supporters of repeal hope senators heed the ruling issued in Los Angeles by US District Judge Virginia Phillips, who said 'don't ask, don't tell' was an unconstitutional violation of the due process and free speech rights of gays and lesbians.
The policy has a "direct and deleterious effect" on the military by hurting recruitment efforts during wartime and requiring the discharge of service members who have critical skills and training, she said.
The Log Cabin Republicans, a Republican gay-rights organisation, sued the federal government in 2004 to stop the policy, and Ms Phillips said she would draft an order within a week doing just that.
The US Department of Justice has not yet said whether it will appeal against the ruling; spokesman Charles Miller said lawyers were reviewing it.