Many people who oppose marriage equality like to suggest that it is the end of the institution of marriage. That isn’t true:
Marriage has, in the past, been about one man/one woman, just as Gallagher says; it’s been an assertion that gender and gender roles are as important as, or even more important than, what you feel in your heart.
Gay marriage is a final, absolute refutation of that logic. If two men can get married, or two women, then marriage must really be not about power, but about love. Gay marriage, then, is radical in the best sense, in that it offers equality and hope not just to gay people, but to children, women, and men of every orientation—even to Gallagher, resist it as she will. Gay marriage is not just about straight people accepting gays into our institutions. It’s about gay people teaching us what those institutions mean. The gay community has given straight people a lot over the years, but surely gay marriage is one of the greatest gift it has offered us.