''I BELIEVE severe punishment is required in this case," the judge said at Allen and Pat's sentencing in November 1997. ''I think they have to be separated. It's the only way to prevent them from having intercourse in the future."
Allen and Pat were lovers, but a Wisconsin statute enacted in 1849 made their sexual relationship a felony. The law was sometimes used to nail predators who had molested children, but using it to prosecute consenting adults -- Allen was 45; Pat, 30 -- was virtually unheard of. That didn't deter Milwaukee County Judge David Hansher. Nor did the fact that the couple didn't understand why their relationship should be a crime. Allen and Pat didn't ''have to be bright," the judge growled, to know that having sex with each other was wrong.
He threw the book at them: eight years for Allen, five for Pat, served in separate maximum-security prisons, 25 miles apart.
If this had happened to a gay couple, the case would have become a cause celebre. Hard time as punishment for a private, consensual, adult relationship? Activists would have been outraged. Editorial pages would have thundered.
But Allen and Patricia Muth are not gay. They were convicted of incest. Although they didn't meet until Patricia was 18 -- she had been raised from infancy in foster care -- they were brother and sister, children of the same biological parents. They were also strongly attracted to each other, emotionally and physically. And so, disregarding the taboo against incest, they became a couple and had four children.
When Wisconsin officials learned of the Muths' relationship, they moved to strip them of their parental rights. The state's position, upheld in court, was that their ''fundamentally disordered" lifestyle made them unfit for parenthood by definition. Allen and Patricia's children were taken from them. Then they were prosecuted for incest and sent to prison.
I wrote about the Muths' case shortly after their conviction, asking why social liberals were not up in arms over it. Where were the people who always insist that the government should stay out of people's bedrooms? That what goes on between consenting adults is nobody's business but their own? That a family is defined by love, not conventional morality? Patricia and Allen Muth were one ''nontraditional" family it seemed no one cared to defend.
But then came Lawrence v. Texas, the Supreme Court's decision in 2003 that the Constitution protects the freedom of Americans to engage in ''the most private human conduct, sexual behavior," when it is part of a willing relationship between adults.
''The petitioners are entitled to respect for their private lives," Justice Anthony Kennedy wrote in striking down the Texas law under which John Lawrence and Tyron Garner had been convicted of homosexual sodomy. ''The state cannot demean their existence or control their destiny by making their private sexual conduct a crime. Their right to liberty under the Due Process Clause gives them the full right to engage in their conduct without intervention of the government."
Armed with Lawrence's sweeping language, Allen Muth appealed his conviction.
The taboo against incest may be ancient, and most Americans may sincerely regard it as immoral or repugnant. But Lawrence was clear: ''The issue is whether the majority may use the power of the State to enforce these views on the whole society through operation of the criminal law." If the Supreme Court meant what it said, Muth argued, his and his sister's convictions for incest were every bit as unconstitutional as the Texas men's convictions for sodomy.
Earlier this summer, the Seventh Circuit Court of Appeals ruled against Muth. But it did so on the strained and narrow ground that since Lawrence had dealt specifically with homosexual sodomy, it could not be invoked retroactively to overturn a conviction for incest. The opinion was written by Judge Daniel Manion, and as legal scholar Matthew Franck observed, Manion must have been ''desperate to avoid the plain consequences of the [Supreme] Court's recent precedents on sexual liberty."
But those consequences cannot be outrun forever. What Manion declined to do, another judge may embrace. (Or perhaps the high court itself will: Muth has until Sept. 20 to file an appeal.) There is simply no principled escape from the logic of Lawrence: If the Constitution forbids the states to criminalize private sexual conduct between consenting adults, lovers who happen to be siblings can no more be sent to prison than lovers who happen to be men.
Dissenting in Lawrence, Justice Antonin Scalia warned that the decision ''effectively decrees the end of all morals legislation." It was a prediction the majority made no effort to refute.
Jeff Jacoby's e-mail address is firstname.lastname@example.org.