Jonathan Turley is the Shapiro professor of public interest law at George Washington University and lead counsel in the “Sister Wives” polygamy case.

The decision this month by a federal court striking down the criminalization of polygamy in Utah was met with a mix of rejoicing and rage. What was an emancipating decision for thousands of plural families was denounced as the final descent into a moral abyss by others.

Former senator Rick Santorum was among the social conservatives trying to claim the moral high ground. He tweeted on Sunday: “Some times I hate it when what I predict comes true” — referring to his 2003 claim that legalizing “consensual sex within your home” would lead to the legalization of polygamy and “undermine the fabric of our society.” (On Wednesday, with no apparent sense of self-contradiction, he expressed outrage over the removal of a Nativity scene at a South Carolina military base, tweeting: “Our Constitution protects free exercise of religion. No govt entity/official has the right to limit that.”)

It’s true that the Utah ruling is one of the latest examples of a national trend away from laws that impose a moral code. There is a difference, however, between the demise of morality laws and the demise of morality. This distinction appears to escape social conservatives nostalgic for a time when the government dictated whom you could live with or sleep with. But the rejection of moral codes is no more a rejection of morality than the rejection of speech codes is a rejection of free speech. Our morality laws are falling, and we are a better nation for it.

In the Utah case, I was the lead counsel for the Browns, the polygamous family featured in the TLC reality program “Sister Wives.” They are members of the Apostolic United Brethren Church, and they have one marriage license and three “spiritual” marriages among them. After the first episode of “Sister Wives” aired, state prosecutors threatened to bring charges under a Utah law that made it a crime when a married person “purports to marry another person or cohabits with another person.” The Browns were under investigation for two years and were publicly called felons before they took prosecutors to court in a challenge to the constitutionality of the law.

The case was never about the recognition of multiple marriages or the acceptance of the religious values underlying this plural family. It was about the right of consenting adults to make decisions for themselves and their families. Judge Clark Waddoups, a conservative George W. Bush appointee, ruled that the criminalization of cohabitation clearly violated the due process clause and the free exercise clause of the United States Constitution.

In doing so, he departed from the prevailing precedent: the Supreme Court’s opinion in Reynolds v. United States , which upheld a ban on polygamy in 1879. Waddoups wrote that courts today are “less inclined to allow majoritarian coercion of unpopular or disliked minority groups, especially when blatant racism . . . religious prejudice, or some other constitutionally suspect motivation, can be discovered behind such legislation.”

Indeed, in Reynolds, religious and racial prejudice were vividly on display. The court unleashed a tirade of indignation and condemnation, stating, “Polygamy has always been odious among the northern and western nations of Europe, and, until the establishment of the Mormon Church, was almost exclusively a feature of the life of Asiatic and of African people.” Just a few years later, the Supreme Court also upheld the criminalization of mixed-race relations in Pace v. Alabama .

The idea that polygamy was a “barbarous practice” and contrary to democratic principles drove the demand in the late 1880s and ’90s that Utah outlaw it as a condition of statehood. And in Mormon Church v. United States (1890), the Supreme Court labeled polygamy as “abhorrent to the sentiments and feelings of the civilized world.”

The stigma attached to polygamy continued to distort legal analysis into this century. As recently as 2006, Utah Justice Ronald Nehring began his opinion in a ruling upholding the criminalization of polygamy by lamenting, “No matter how widely known the natural wonders of Utah may become, no matter the extent that our citizens earn acclaim for their achievements, in the public mind Utah will forever be shackled to the practice of polygamy.” Nehring frankly admitted that this hostility “has been present in my consciousness, and I suspect has been a brooding presence . . . in the minds of my colleagues, from the moment we opened the parties’ briefs.” Rather than overcome that prejudice, Nehring not only yielded to it but warned any Utah judge of the peril of being the first to recognize the rights of polygamists: “I have not been alone in speculating what the consequences might be were the highest court in the State of Utah the first in the nation to proclaim that polygamy enjoys constitutional protection.”

Well, it wasn’t. A federal judge in Utah assumed that burden. Gov. Gary Herbert objected to the court making “decisions on social issues.” (He has not yet announced an appeal.) Waddoups, however, was not dictating a decision on a social issue but rather saying that governments could not impose a single version of morality. He limited prosecution under Utah’s anti-polygamy law to cases of bigamy, where someone acquires more than one marriage license — which is an offense more common to monogamous couples, who care about state recognition, than polygamists, who care about spiritual recognition.

Across the country, the era of morality codes is coming to an inglorious end. This year, the Supreme Court struck down part of the Defense of Marriage Act barring the federal recognition of same-sex marriage. And this week, the New Mexico Supreme Court and another federal judge in Utah struck down the ban on same-sex marriage in those states — bringing the number to 18 states (plus the District of Columbia) where same-sex couples can marry. Meanwhile, Virginia recently repealed its 1877 cohabitation law and Colorado replealed a criminal adultery law from the 1850s — both relics of a time when states used their criminal codes to force citizens to comply with the religious values of their neighbors.

Most states have wisely turned away from absurd laws criminalizing masturbation and fornication. Obscenity laws have also been curtailed by the Supreme Court in deference to the First Amendment.

Still rightly on the books are laws against bestiality, which involves an obvious lack of consent as well as manifest harm. Likewise, incest bans are based on claims of medical, not moral, harm.

Once any crimes or abuses are stripped away in cases like the Browns’, what remains is religious animus. Yet, polygamy is widely practiced around the world by millions of families and was condoned by every major religion — from Judaism to Christianity to Islam — at one time. While plural families are called polygamists in our popular lexicon, “polygamy” actually refers to a broad array of plural relationships, from polygyny (one husband and multiple wives, like the Browns) to polyandry (a single wife and multiple husbands) to polyamory (couples who reject the exclusivity of sexual relations). The vast majority of these families are based on consenting relations among adults without abusive or criminal histories.

Critics often ignore these other plural relationships (and even polygynists like the Browns) in favor of a stereotype of “compound polygamists,” living in remote walled communities where women appear captive and molestation flourishes. It is Warren Jeffs, not Kody Brown, whom critics want to invoke in debating decriminalization — a sinister figure in a secluded compound where women wear prairie outfits and hairdos from the 19th century.

Obviously, there will always be abusers like Jeffs among polygamists — just as there are abusers among monogamists. However, it is no more persuasive to criminalize all plural relationships because of a small number of abusive individuals than it would be logical to outlaw monogamy based on the convicted spouse- and child-abusers in conventional marriages.

One of the great ironies about the focus on compound polygamists is the circular logic of criminalization. The government first declared polygamists felons and then pointed to their hiding as evidence of their guilt. But decriminalization will allow these families to be plural, open and law-abiding as they reintegrate into society.

In truth, 19th-century Americans were no more moral than we are today. It simply appeared that way with the imposition of official morals, including (as Santorum recalls so fondly) being told whom we could love in our own homes. It is not a single moral voice that is heard today but a chorus of voices. Each speaks to its own values but joins around a common article of faith: the belief that morality is better left to parents than to politicians.

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