A map and chart of how the law and public opinion on gay marriage are changing in America

ON April 28th America's Supreme Court begins hearing arguments about gay marriage. At issue is whether the minority of states that still ban it should be allowed to do so. Traditionalists insist that marriage is a

matter for elected state lawmakers

to regulate. Not so, say proponents of same-sex marriage: the constitution requires the states to give all people within their jurisdiction

"the equal protection of the laws"

, and that means they can't limit wedlock to heterosexuals. Public opinion has shifted faster than a cheetah with its tail on fire. In 2004, when the first gay marriages were recognised in Massachusetts, no state had a majority in favour of such unions. Today most do. And the least gay-friendly state, Alabama, is about where today's most gay-friendly state, Vermont, was a decade ago.

Read more here.