This week federal judges overturned gay-marriage bans in Oregon and Pennsylvania. Nineteen states, covering 43% of the population, now allow such unions; bans in seven more have been scrapped, but the rulings have been stayed pending appeals. Last June the Supreme Court overturned part of the federal Defence of Marriage Act (DOMA); since then judges across the country have applied the legal reasoning in that case, which said DOMA “demeans” gay couples, to state bans.

The chart shows states with gay marriage by the date they legalised it and the proportion of residents who say they are conservative. Early movers were mostly liberal, but by no means all. The holdouts are all fairly conservative (see the right-hand side of the chart). With so many lawsuits pending, it is a fair bet that gay marriage will be back at the Supreme Court before long.