The modern era of the movement for access to marriage for same-sex couples began in Hawaii in 1993. Of that there is no doubt. That year the Hawaii Supreme Court ruled that the state's ban on same-sex marriage was unconstitutional sex discrimination under the Hawaii state constitution. The court sent the case back to the trial court and instructed the state to justify the exclusion by proving that it was "necessary" to protect a "compelling state interest." Although the people of Hawaii cut short the process begun by that court ruling by passing a constitutional amendment, the ruling served the purpose of demonstrating that is was possible to bring a court challenge and succeed. The rest is history, and of course it is history still in the making.
Well today Hawaii Governor Neil Abercrombie signs a bill creating civil unions. The status confers all the state based consequences of marriage. Both same-sex and different-sex couples can enter civil unions. You can watch the signing live, at 7 pm Eastern time, here. Lambda Legal has prepared a terrific explanation of the new law which you can read here.
The most recent three states to create such a comprehensive status are Hawaii, Illinois (civil union - 2011), and Nevada (domestic partnership - 2009). All three are open to different-sex couples. I hope this marks a trend that will continue. California and Washington allow different-sex couples to enter domestic partnerships if one person is at least 62 years old. (When a divorced person who was married more than 10 years turns 62, that person becomes eligible for social security based on the work record of his or her ex-spouse. Remarriage destroys that eligibility, but domestic partnership or civil union status does not.)
I hope that someday the official name of the civil status that all couples can choose will be something other than marriage. (I describe my views in more detail here.) I like civil partnership, but I'll take civil union.
My favorite place in the world is Kauai. I can highly recommend it for those wishing to formalize their relationships in, well, paradise.