Bush has said he would defend it and would support if necessary a constitutional amendment enshrining it, but no such announcement was anticipated at this time.
"We continue to look very closely at this issue," McClellan said. "If there is something he has to say further on this we will let you know."
Massachusetts' high court recently ruled the state must recognize homosexual marriages, not just some form of civil union. The state opened a constitutional convention Wednesday to consider the issue.
Bush has said he would back an amendment supporting traditional marriage if activist judges continued to redefine the institution. Proposed legislation supporting such an amendment is currently in the House of Representatives.
The Washington Post said Bush is prepared to endorse language introduced by Rep. Marilyn Musgrave, R-Colo., that would ban gay marriage but permit civil unions and same-sex partnership arrangements that exist in Vermont and California.
Musgrave's proposal, called the Federal Marriage Amendment, states: "Marriage in the United States shall consist only of the union of a man and a woman. Neither this Constitution or the constitution of any State, nor state or federal law, shall be construed to require that marital status or the legal incidents thereof be conferred upon unmarried couples or groups."
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