Many argue that polygamous marriages are typically sites of abuse, inequality in power and coercion. Some refer to sociological research showing a host of ills that are associated with polygamous family structures. These claims are both true and beside the point. Yes, it’s true that many polygamous marriages come from patriarchal systems, typically employing a “hub and spokes” model where one husband has several wives who are not married to each other. These marriages are often of the husband-as-boss variety, and we have good reason to suspect that such models have higher rates of abuse, both physical and emotional, and coercion. But this is a classic case of blaming a social problem on its trappings rather than on its actual origins.

After all, traditional marriages often foster abuse. Traditional marriages are frequently patriarchal. Traditional marriages often feature ugly gender and power dynamics. Indeed, many would argue that marriage’s origins stem from a desire to formalize patriarchal structures within the family in the first place. We’ve pursued marriage equality at the same time as we’ve pursued more equitable, more feminist heterosexual marriages, out of a conviction that the franchise is worth improving, worth saving. If we’re going to ban marriages because some are sites of sexism and abuse, then we’d have to start with the old fashioned one-husband-and-one-wife model. If polygamy tends to be found within religious traditions that seem alien or regressive to the rest of us, that is a function of the very illegality that should be done away with. Legalize group marriage and you will find its connection with abuse disappears.

Another common argument, and another unsatisfying one, is logistical. In this telling, polygamous marriages would strain the infrastructure of our legal systems of marriage, as they are not designed to handle marriage between more than two people. In particular, the claim is frequently made that the division of property upon divorce or death would be too complicated for polygamous marriages. I find this argument eerily reminiscent of similar efforts to dismiss same-sex marriage on practical grounds. (The forms say husband and wife! What do you want us to do, print new forms?) Logistics, it should go without saying, are insufficient reason to deny human beings human rights.

If current legal structures and precedents aren’t conducive to group marriage, then they will be built in time. The comparison to traditional marriage is again instructive. We have, after all, many decades of case law and legal organization dedicated to marriage, and yet divorce and family courts feature some of the most bitterly contested cases imaginable. Complication and dispute are byproducts of human relationships and human commitment. We could, as a civil society, create a legal expectation that those engaging in a group marriage create binding documents and contracts that clearly delineate questions of inheritance, alimony, and the like. Prenups are already a thing.

Most dispiriting, and least convincing, are those arguments that simply reconstitute the slippery slope arguments that have been used for so long against same sex marriage. “If we allow group marriage,” the thinking seems to go, “why wouldn’t marriage with animals or children come next?” The difference is, of course, consent. In recent years, a progressive and enlightened movement has worked to insist that consent is the measure of all things in sexual and romantic practice: as long as all involved in any particular sexual or romantic relationship are consenting adults, everything is permissible; if any individual does not give free and informed consent, no sexual or romantic engagement can be condoned.

This bedrock principle of mutually-informed consent explains exactly why we must permit polygamy and must oppose bestiality and child marriage. Animals are incapable of voicing consent; children are incapable of understanding what it means to consent. In contrast, consenting adults who all knowingly and willfully decide to enter into a joint marriage contract, free of coercion, should be permitted to do so, according to basic principles of personal liberty. The preeminence of the principle of consent is a just and pragmatic way to approach adult relationships in a world of multivariate and complex human desires.

Progressives have always flattered themselves that time is on their side, that their preferences are in keeping with the arc of history. In the fight for marriage equality, this claim has been made again and again. Many have challenged our politicians and our people to ask themselves whether they can imagine a future in which opposition to marriage equality is seen as a principled stance. I think it’s time to turn the question back on them: given what you know about the advancement of human rights, are you sure your opposition to group marriage won’t sound as anachronistic as opposition to gay marriage sounds to you now? And since we have insisted that there is no legitimate way to oppose gay marriage and respect gay love, how can you oppose group marriage and respect group love?

I suspect that many progressives would recognize, when pushed in this way, that the case against polygamy is incredibly flimsy, almost entirely lacking in rational basis and animated by purely irrational fears and prejudice. What we’re left with is an unsatisfying patchwork of unconvincing arguments and bad ideas, ones embraced for short-term convenience at long-term cost. We must insist that rights cannot be dismissed out of short-term interests of logistics and political pragmatism. The course then, is clear: to look beyond political convenience and conservative intransigence, and begin to make the case for extending legal marriage rights to more loving and committed adults. It’s time.