Delaware became the eleventh state to legalize gay marriage (plus Washington D.C., which, like gay people, deserves equal representation). The Democrat-controlled state senate voted to approve the law, and Delaware Governor Jack Markell signed it within minutes. Civil unions were already legal in Delaware, but more and more, people and the legislatures they represent are rejecting civil unions in favor of full legalized marriage for the same reasons that "separate but equal" laws were enacted but struck down in the civil rights era. Both civil unions and "separate but equal" laws served as a way to offer similar rights to a subjugated group without the dominant group having to intermingle too closely. In both cases, the middle-ground laws lasted for a while and then were rejected once voters rubbed the sleep out of their eyes some years later, and left-leaning politicians seamlessly (ish) "evolved" into the position of greater equality.
It's a silly dance we do, but it ends in equality. In fact, the best part about Delaware legalizing same-sex marriage is that it almost doesn't feel like big news anymore. It certainly is big news, but it's big news that seems to be happening more frequently, and that feels inevitable. That said, Delaware being the 11th state to sign marriage equality into law means that there are 39 states left to go. More will flip soon, and plenty of deep red states won't budge for a while, but this is one fight that will only move in one direction.