Gay marriage opponents have filed an appeal in the Supreme Court in an 11th hour attempt to block the district’s gay marriage law.
From tomorrow, gay couples in DC will be able to apply for marriage licences but opponents have asked for an emergency stay.
They have demanded a voter referendum on the matter, although this request has been denied by lower courts.
Gay rights attorney Mark Levine told Associated Press that the appeal would have argued that allowing gay marriage violates opponents’ constitutional rights.
But he estimated it would be highly unlikely for the court to agree.
Gay marriage is currently legal in five states but the right has never been granted by voters. Instead, marriage equality rights have always been granted by courts or legislature.
Voters in California repealed a gay marriage law in 2008, while Maine voters prevented a similar law being enacted last autumn.
The gay marriage bill in DC was signed by mayor Adrian Fenty in November.
The district will follow Massachusetts, Vermont, Iowa, New Hampshire and Connecticut in allowing gay couples to marry.