Civil rights groups that campaigned against California's same-sex marriage ban have lost an attempt to withhold internal memos and e-mails from lawyers for the other side.
U.S. District Chief Judge Vaughn Walker ruled Monday that the groups must surrender the campaign documents as evidence in a federal trial on the constitutionality of Proposition 8.
Walker's decision upholds a previous ruling by a federal magistrate.
The trial is the first in federal court to examine whether the U.S. Constitution prevents states from outlawing gay marriage.
The American Civil Liberties Union, one of the three groups that must turn over campaign materials, previously said it would appeal if Walker upheld the magistrate's order.
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