Two recent events in the United States have brought the issue of same sex marriage back to the top of the news. Firstly, on election day, 6 November, three states legalized same sex marriage and a fourth voted down a ban on same sex marriage. This brought the number of states that have approved gay marriage to nine.

Secondly, the US Supreme Court announced on 7 December that it would take up two cases relating to same sex marriage. They will hear arguments on the cases in the spring of 2013 and rule on them before adjourning in the summer.

The first case will decide whether California voters acted legally when they passed so called Proposition 8 in 2009, which overruled a decision by the California Supreme Court that had permitted gay marriage.

The second case, from New York, challenges a federal law called the Defense of Marriage Act (DOMA), passed in 1996. DOMA, among other things, defined marriage as between only a man and a woman for the purpose of enforcing hundreds of federal laws and …