Our era’s radical Republicans are willing to take a conservative position when it suits them. Thus, during the recent Supreme Court argument regarding same-sex marriage, the right-wingers on the Court pointed out that marriage has involved a man and a woman for thousands of years. From ThinkProgress:
The Court’s conservatives [sic] fixated upon their belief that same-sex marriages are a very new institution. “Every definition [of marriage] I looked up prior to about a dozen years ago,” Chief Justice John Roberts claimed, limited marriages to opposite-sex couples. Advocates for equality, Roberts continued, are “seeking to change what the institution is.” Meanwhile, Justice Samuel Alito argued that even “ancient Greece,” a society he perceived as welcoming to same-sex relationships, did not permit same-sex marriage. Justice Antonin Scalia insisted that “for millennia, not a single society” supported marriage equality.
A natural response would have been: “Of course, and now we’re changing that. Sometimes we make progress”. Justice Ginsburg, however, pointed out that for thousands of years marriage was legally defined as a relationship between a dominant man and a subordinate woman. A further ThinkProgress article on the subject quotes the 18th century legal authority Sir William Blackstone:
…the very being or legal existence of the woman is suspended during the marriage, or at least is incorporated and consolidated into that of the husband; under whose wing, protection and cover, she performs everything.
Traditionally, wives were subservient to their husbands. Being married wasn’t a relationship that two men or two women would ordinarily enter into. Today, however, the law considers marriage to be a relationship between equals. Since marriage is now egalitarian from a legal perspective, it makes sense for anyone who wants an equal partner, whether that partner is of the opposite or same sex, to want to be married. Since there are benefits to being married, and since being able to procreate isn’t a requirement, justice dictates that any two adults who want to get married should be allowed to.