Eleven years after Massachusetts became the first state to recognize the marriages of same-sex couples, gay marriage is now legal in Maine and 36 other states, despite opponents’ dire and unfounded claims that this movement poses a threat to the social order.

Now an entire country has embraced equal marriage rights at the ballot box — a worldwide first. And, as in the U.S., mainstream marriage in Ireland will benefit by being open to more citizens — because legalizing same-sex unions is just the latest in a series of changes that have transformed this tradition for the better.

Marriage originated as a way to consolidate property and cement alliances between families. That two people might marry because they had fallen deeply in love is a relatively new idea, dating only to the 1700s.

And the concept of gender equality within marriage is even newer than love matches. Before Congress passed the Equal Opportunity Credit Act in 1974, for instance, married women couldn’t get credit in their own name. They had to have a man co-sign any credit application, and when deciding how much credit to grant, banks could discount the value of a female credit applicant’s wages by up to 50 percent.

Wives were also discriminated against in their private lives: It was taken for granted that by agreeing to marry a man, a woman was also consenting to have sex with him any time he wanted to. Marital rape was legal nationwide until 1976, when Nebraska became the first state to abolish a provision barring prosecution in the rape of one’s spouse. By 1993, all 50 states had criminalized spousal rape.

Like the extension of credit, the abolition of the marital rape exemption to sexual assault laws was a major advance for women, recognizing them as separate individuals with rights of their own within marriage.

Now Ireland – where homosexuality itself was a criminal offense only 22 years ago — is setting the pace for social change. Observers say voters were swayed by a door-to-door marriage equality campaign that made them aware that what their gay, lesbian and bisexual neighbors wanted nothing more or less than the same rights everyone else already had.

The Irish gay-marriage victory is a deep-rooted shift but not an apocalyptic one. The only change will be that more people will be able to share their lives with those they love — and that can only be a good thing.