My guilty pleasure is watching Judge Judy during my lunch break. Sandwich and cuppa in hand, I love watching her harangue dead-beat parents over child support arrears, sniff out which lovesick teenager is responsible for keying an ex-boyfriend's car, and lecturing separated couples fighting over who gets the washing machine and the cable bill.
Often, she will ask why they didn't bother to marry: 'You're committed enough to make a baby, but not to get married?' she'll rhetorically ask in her no-nonsense Brooklyn Jewish grandmother accent. 'We have courts for marriages that break up but not for when living together doesn't work out,' she explains.
In a nutshell, Judge Judy is explaining the modern democratic state's interest in marriage: recognising the contractual rights and obligations of two people who share resources and (where they exist) rights and responsibilities to children.
The state doesn't have an opinion on whether God approves of the union because theocracy went out of fashion in the West, along with the Divine Right of Kings. These days in Australia, the state doesn't even care to enforce sexual exclusivity of partners, although once upon a time that was a major element of marital law. Divorce is all about distribution of assets and establishing proper care of the kids. So why the brouhaha over marriage for gay people?
Since time immemorial, different societies and cultures have developed all sorts of rules and taboos about marriage, which makes for fascinating reading and belies the notion that there is a single, eternal concept of marriage that straight people can access but gays may not. Some types of marriage permissible in different times and cultures are not accepted under current Australian law, other types are perfectly legal here but a big no-no in other times and places.
Take interreligious marriages, for example. In Australia, a Satanist can marry a Jedi Knight and no-one gives two hoots, but a fourth century Christian couldn't even dine with a Jewish neighbour, let alone marry him, thanks to the Council of Elvira. Things have relaxed a bit since then, but even in 1938 my CofE grandfather had to marry his Catholic bride 'behind the altar' and her relatives wouldn't darken their doorstep.
Muslim men have to restrict themselves to four wives, but fundamentalist Mormons are good to go with any number. Polygyny was common enough in ancient Judaism, the record being held by King Solomon and his thousand wives and concubines.