New York is reportedly on the brink of marriage equality after another Republican senator said yesterday he would support the move.
Governor Andrew Cuomo introduced the legislation in both houses yesterday.
With the new support of Sen Roy McDonald, 31 out of 62 Senate members are expected to back it, leaving the bill in need of just one more vote.
Another Republican and three Democrats have also said they will back the bill after opposing gay marriage in the past.
In the Democrat-controlled Assembly, which has backed gay marriage a number of times, the bill is expected to pass.
Mr Cuomo has said before that he will not introduce a bill until he is sure it will succeed. A gay marriage bill suffered a surprise defeat in 2009 after support levels were overestimated.
This bill does not offer protection to individuals who refuse to officiate or provide services to gay weddings. However, religious groups are not obliged to perform the ceremonies.
If the bill passes, it will come into law 30 days after Mr Cuomo signs the legislation, making New York the sixth US state to allow gay couples to marry.
Massachusetts, Connecticut, Iowa, New Hampshire, Vermont and Washington DC currently have marriage equality.
California’s ban is under review