Gay and lesbian plaintiffs challenging California's ban on same-sex marriage inspected the original copy of the US Constitution on Monday on the eve of a landmark US Supreme Court hearing.
Paul Katami and Jeff Zarrillo joined Kris Perry and Sandy Tier on the steps of the National Archives, where they posed for news photographers but declined to speak to reporters.
They then went indoors "to view the US Constitution and reflect on the importance of their case for gay and lesbian couples across the nation," said the American Foundation for Equal Rights, which is supporting their case.
The Supreme Court will hear oral arguments Tuesday on the two couples' challenge to Proposition 8, the California referendum item in 2008 that struck down the state's same-sex marriage initiative.
On Wednesday the highest court in the land will consider the Defense of Marriage Act, which denies married gays and lesbians the same rights and privileges under federal law as wedded heterosexual couples.
Vigils were planned overnight Monday, while the Human Rights Campaign, a major LGBT rights group, urged supporters to dress in red for a rally at the Supreme Court steps Tuesday "to show your support for marriage equality."
Opponents of same-sex marriage meanwhile planned their own "march for marriage" from the National Mall to the court -- with women invited to dress in red, children in white and men in blue.
"We believe it is imperative that political leaders, the media, and the culture see that we care about protecting marriage enough to stand up and march for it," said its organizers, the National Organization for Marriage.
Opinion polls have pointed to a shift in American public opinion on same-sex marriage, with a majority now in favor. Social conservatives, including the Catholic and evangelical churches, remain staunchly opposed.