The catch is that all of these are blue states that have voted Democratic in at least five of the past six presidential elections. In Republican-leaning red states, which uniformly have banned gay marriage, few seem to be having second thoughts. For the near future, the nation appears locked onto a trajectory in which almost all reliably blue states will establish gay marriage (or civil unions) and possibly not a single reliably red state will follow.
Even some liberal justices this week appeared wary of preempting this sorting out. "If the issue is letting the states experiment and letting the society have more time to figure out its direction, why is taking a case now the answer?" asked Justice Sonia Sotomayor.
That approach could mean a longer-lasting patchwork on gay marriage than many now imagine. In the absence of national rules from Congress or the Supreme Court, the country often has let "the states experiment" with inimical courses for a very long time on questions at least as weighty.
The most obvious is slavery, which existed in the South until the Civil War ended it almost nine decades after Vermont first banned the practice in its colonial constitution. After the war, Tennessee in 1882 ignited a burst of laws across the South mandating racial segregation. Even after the Supreme Court upheld these "separate but equal" laws in its 1896 Plessy v. Ferguson decision, few jurisdictions outside of the South followed: By 1915, the movement for legal segregation had already crested "somewhere south of Wilmington [Del.] and east of Oklahoma City," as Joel Williamson wrote in his book The Crucible of Race. Yet, even as most states spurned segregation, the South defiantly maintained it until Congress intervened with the 1964 Civil Rights Act.
On interracial marriage, the state chasm endured even longer. The first laws banning it trace back to the 1600s (in Maryland and Virginia), and the states decisively split in 1780 when Pennsylvania became the first to repeal its prohibition. Yet the U.S. Supreme Court didn't ban all such miscegenation laws until 1967, at which point 16 states still had them on the books.
Not only racial issues have durably divided the states. All states didn't mandate compulsory education until 1918, 66 years after the first one (Massachusetts) did. Congress didn't establish the federal minimum wage until 1938, a quarter century after Massachusetts established the first one for women and children.
Looking forward, a key question on gay marriage is whether the intensity of modern media and communications makes such disparities among the states less tenable. The dawn of television hastened segregation's demise; it seems dubious that its daily indignities could have survived as long amid 24-hour cable and viral videos. (Imagine enforcing back-of-the-bus rules against people filming iPhone videos that might reach CNN in hours.) Today, the increasingly positive images of gay men and women in the popular culture blanketing all regions probably help explain the growing public support for same-sex rights, including marriage.