A poll says that just over half of Republicans support some form of legal recognition for gay couples.
The Public Policy Polling survey asked 1,000 people who identified as Republicans about their views on marriage equality.
Only 12 per cent said gay couples should be allowed to marry. Support for civil unions was higher, with 39 per cent agreeing with them.
This meant that 51 per cent back either marriage equality or civil unions.
But 48 per cent said there should be no recognition at all of gay relationships.
Support for marriage equality was highest among high-income respondents as 24 per cent in this category said gays should be able to wed.
Last month, another American poll suggested that just over half of voters support marriage equality.
The CNN poll found that 51 per cent of the 824 adults surveyed said gay couples should be allowed to wed.
Among those under 50, support levels rose to 60 per cent.
CNN polls in 2008 and 2009 found that just 44 per cent of those surveyed supported gay marriage.