The US Supreme Court is to decide on Friday whether to deal now with whether the bans on gay couples marrying across many parts of the United States are unconstitutional.

The court could decide instead to focus on whether Congress can prevent gay couples who are married in states that permit it should receive federal benefits that straight couples are entitled to.

If it opts to review the specifics of a state’s ban, it is likely to focus on the dispute over Proposition 8, the voter initiated constitutional amendment that banned gay couples from marrying in California. It has been ruled as a ban that breaks the Californian constitution already, although it is the subject of an appeal.

If the court did make a decision in favour of same-sex marriage in one state, such as California, it would overturn the bans in 31 states.

Andrew Koppelman, a professor of law and political science at Northwestern University has urged them not to hear such a case. He told the Associated Press: “What do they have to gain by hearing this case? Either they impose same sex marriage on the whole country, which would create a political firestorm, or they say there’s no right to same-sex marriage, in which case they are going to be reversed in 20 years and be badly remembered. They’ll be the villains in the historical narrative.”

Chad Griffin, president of the Human Rights Campaign told USA Today: “2012 has already been the watershed year in the history of this movement. It’s so clear where this country’s headed on this issue.”

The White House is not defending any cases relating to the Defense of Marriage Act that bans same-sex marriage so the Republicans in the House of Representatives stepped in to take up the defence of the law in court.

In papers filed to the Supreme Court, Paul Clement a lawyer representing the House of Representatives said: “The Defense of Marriage Act does not bar or invalidate any state-law marriage, but leaves states free to decide whether they will recognize same-sex marriage.”