By Grant McCool

NEW YORK, Sept 19 (Reuters) - U.S. officials must hand over a 2004 legal memorandum on the constitutionality of requiring non-governmental, U.S.-based HIV/AIDS groups to make a pledge opposing prostitution when they work abroad, a federal appeals court ruled on Wednesday.

The ruling follows a July 2011 decision by the court that struck down the "pledge requirement" contained in the U.S. Leadership Against HIV/AIDS, Tuberculosis, and Malaria Act of 2003. The court said at the time that the pledge violated First Amendment free speech rights.

Wednesday's ruling by a three-judge panel of the 2nd U.S. Circuit Court of Appeals upheld a trial judge's order in favor of the Brennan Center for Justice at New York University School of Law in obtaining a February 2004 memorandum by the Department of Justice's Office of Legal Counsel.

The Brennan Center, a public policy and law institute, had sued under the Freedom of Information Act in October 2009. In its lawsuit it had argued that the OLC had reversed course on the constitutionality of the pledge.

The lawsuit said that for 18 months, the memorandum served as the basis for the administration of former president George W. Bush's policy to not enforce the pledge. At that point the OLC decided the pledge might be constitutional after all and began enforcing it, the lawsuit said.

A redacted version of the memorandum was provided during the litigation.

Apart from the Department of Justice, the Department of Health and Human Services and the U.S. Agency for International Development were named as defendants because they asked the Department of Justice for advice on the constitutional issue of the pledge.

The pledge requirement is still in force under the administration of President Barack Obama.

The issue could come before the U.S. Supreme Court in its upcoming term because USAID appealed the 2nd Circuit's decision of last July. The high court would consider whether the "pledge requirement" violates free speech rights of domestic non-governmental organizations that receive federal funding for their programs in other countries.

In its ruling on Wednesday, the panel of circuit judges Guido Calabresi, Robert Sack and Peter Hall concluded that there was no dispute that the memorandum was "predecisional and deliberative." The government could not refer to "a protected document as authoritative" and "then shield the authority upon which it relies from disclosure."

In the lower court, U.S. District Judge Victor Marrero had also ordered the release of two draft OLC memoranda of July 2004. The appeals court reversed him "because there is insufficient evidence that those memoranda were expressly adopted or incorporated by reference" as policy.

A spokeswoman for the Department of Justice declined to comment on the decision.

The Brennan Center said in a statement that the ruling "is an important victory for all groups and organizations who face questionable government restrictions."

The cases are Brennan Center for Justice at New York University School of Law v. U.S. Department of Justice, 2nd U.S. Circuit Court of Appeals, No. 11-4599; U.S. Agency for International Development v. Alliance for Open Society International Inc, U.S. Supreme Court, No. 12-10

For Brennan Center: Dorothy Heyl, Elizabeth Virga of Milbank, Tweed, Hadley & McCloy.

For Department of Justice: Sharon Swingle, Benjamin Torrance, Sarah Normand, Beth Brinkmann and Michael Raab, Office of the U.S. Attorney for the Southern District of New York. 

(Additional reporting By Jonathan Stempel)

Follow us on Twitter @ReutersLegal | Like us on Facebook