Good law is evenhanded law, forbidding the rich as well as the poor to sleep under bridges (as Anatole France once observed with a snicker). Written to attract support from legislators who might not be comfortable with actual gay marriage, the civil union bill passed last week by Illinois’s General Assembly doesn’t limit its blessings to gay and lesbian couples in love.

Far from it. As I’ll get to in a minute, the legislation might turn out to be most useful to gay and lesbian couples who have fallen out of love.

Also, elderly straight people.

Here’s the pertinent language: “‘Civil union’ means a legal relationship between 2 persons, of either the same or opposite sex.” Couples of the opposite sex can already get married—who among them would choose the lesser civil union instead? Representative Greg Harris, the Chicago Democrat who sponsored the bill in the house, explains: “I think that some of my colleagues don’t have a lot of gay or lesbian couples in their districts, but they know scores of heterosexual senior citizens whom this might benefit. Senior citizens are the single largest beneficiary group in the state.”

The bill’s charming conceit is that a civil union is something just like, yet other than, a marriage—and that’s why it should interest anyone who doesn’t exactly want to get married.

“In senior centers we encounter this all the time,” Harris tells me. “Somebody was married 40 years, say—they’re a widow or widower. Four years later the surviving spouse, who’s very elderly, meets someone and falls in love. But should they get remarried they stand to lose their pension or social security benefits. For someone on a fixed income scraping by, that’s a big problem.”

Yet by not marrying, Harris continues, they deny themselves all the legal rights that each wants the other to have. Such as health care power of attorney, for instance, the right to make the wrenching decisions required as one or the other approaches death. And the simple right of either to sit at the other’s bedside. All these rights so precious in the twilight years of marriage can now can be theirs through a civil union—yet it won’t be marriage.

And because it isn’t marriage, civil union should also appeal to same-sex straight people—to two old men, for example, who look around, realize they’re the last ones standing, and decide to look after each other. For senior citizens, civil union sounds like a godsend.

For authors of the civil union bill, though, it’s a collateral benefit. When I asked Camilla Taylor—a senior staff attorney in the midwest office of Lambda Legal, where the bill was written three years ago—for the ways in which the lives of the people for whom the law was primarily intended would become better, she didn’t know where to start. So she referred me to a handbook from the Lesbian and Gay Bar Association of Chicago called Strangers in the Eyes of the Law: 648 Reasons Why Marriage Equality Matters.

The 648 turn out to be a list of the “rights, protections and responsibilities” that come with marriage in Illinois, many so obscure that no one would ever think of them ahead of time, yet collectively transformational. For instance, if someone married wins the lottery, the spouse is automatically co-owner of the prize. A mobile home owned by either a disabled veteran or the spouse is exempt from taxation. A candidate running for a local school council must disclose the spouse’s economic interests.

The introduction to this handbook frames the history of marriage as an unending saga of rights struggling to catch up with privileges: “It simply is not accurate to say that marriage has been the same throughout history,” it argues. In biblical times “husbands took multiple wives.” Later, spouses would be “chosen by families who sought to unite their fortunes, not by two people who fall in love.” And not so long ago, right here in the United States, “marriage was once a tool that took all legal and political rights of a woman and bestowed them on her husband.”

The civil union bill is a response to this sorry history—but we need to keep reminding ourselves that a civil union is not a marriage. And if our subject is the bill’s manifold blessings, let’s not overlook the blessed usefulness of legal obfuscation.

The legislation’s formal title, the Illinois Religious Freedom Protection and Civil Union Act, is as good an example as any of the political delicacy called into play. Legislators who wish to be seen as guardians of old-fashioned matrimony can tell constituents who care that the immediate threat is over and the Illinois Marriage and Dissolution of Marriage Act has been successfully defended. Traditional heterosexual marriage is still the only marriage countenanced by the laws of Illinois.

Civil union is simply something uncannily similar to marriage—so similar that anyone in a civil union “is entitled to the same legal obligations, responsibilities, protections, and benefits” that spouses receive in Illinois.

And when a civil union is dissolved, it is so astonishingly like divorce that the civil union act doesn’t bother to describe the process, instead simply declaring that the relevant provisions of the Illinois Marriage and Dissolution of Marriage Act “shall apply.”

The Illinois Marriage and Dissolution of Marriage Act, dating back to 1997, is a massive piece of legislation that never quite pins down what a marriage legally is, but is extremely clear about what it isn’t. Only a marriage “between a man and a woman licensed, solemnized and registered as provided in this Act” is valid in Illinois, it says. “A marriage between an ancestor and a descendent or a brother and a sister” is prohibited; so is “a marriage between an uncle and a niece or between an aunt and a nephew.”

And so, explicitly, is “a marriage between 2 individuals of the same sex.” And if anyone still doesn’t get the point, the act makes it a third time: “A marriage between 2 individuals of the same sex is contrary to the public policy of this State.”

A marriage-rights bill written to reverse this policy would almost certainly have gone down to defeat—it would have lost the votes of principled conservatives who wanted to do right by both homosexuals and matrimonial tradition and of cynics whose price for a yes vote was semantic games.

So credit goes, I guess, to the Catholic church for reading the Illinois Religious Freedom Protection and Civil Union Act and seeing through the games. To the Catholic Conference of Illinois, civil union is a stalking horse for legal same sex marriage—which is exactly what its champions intended it to be. “We’re not finished, not by a long shot,” says Camilla Taylor.

The Catholic Conference of Illinois—the public policy arm of the state’s bishops, led by Cardinal Francis George—predicted in a November 22 statement that passage of the bill “will not appease those who wish to redefine the institution of marriage.” Cardinal George added a personal note: “Everyone has a right to marry, but no one has the right to change the nature of marriage. Marriage is what it is and always has been, no matter what a legislature decides to do. Sexual complementarity is the core of marriage.”

The bishops were unimpressed by the disclaimer in the civil union bill written to guarantee the “religious freedom protection” mentioned in the title. It says, “Nothing in this Act shall interfere with or regulate the religious practice of any religious body. Any religious body, Indian Nation or Tribe or Native Group is free to choose whether or not to solemnize or officiate a civil union.” In the eyes of the bishops, this guarantee missed the point. The question isn’t whether the Catholic Church or any other church is free not to solemnize a civil union. It’s whether it’s free not to recognize one.

Even before the new law was passed, says Taylor, service providers such as Catholic Charities were not free under Illinois law to discriminate on grounds of sexual orientation—though in her view faith-based service providers imperfectly walked this line. Now, with push coming to shove, the bishops look ahead to the church being dragged into court to answer suits demanding that Catholic agencies place adoptive or foster children with a couples in same-sex civil unions; that Catholic camps, retirement homes, and other institutions welcome these couples; and that Catholic employers offer them family benefits.

The Catholic Conference of Illinois must wish the church were as free not to acknowledge civil unions as jurisdictions beyond Illinois are. I’m speaking here of every state that doesn’t recognize civil unions or same-sex marriages—most states by far—and of the federal government, which in 1996 tried to head off those marriages by passing the Defense of Marriage Act. DOMA defines marriage as meaning “only a legal union between one man and one woman as husband and wife,” and it permits states to ignore claims that arise from same-sex marriages made in other states where they’re legal.

Curiously, DOMA makes no mention of civil unions, a loophole its drafter may one day regret. Then again, he already regrets the whole thing. Among the DOMA’s many critics is Bob Barr, the Georgia congressman who wrote the law but later repudiated it as an affront to federalism—Washington was sticking its nose into the states’ business, siccing them on same-sex marriage initiatives wherever they might pop up.

The states didn’t need the encouragement. Though they generally respect one another’s laws—the legal term is comity—they can balk when something legal in one state affronts another, such as the marriage of two 12-year-olds, legal where it happened but beyond the pale the next state over.

“The vast majority of the states in the country have passed laws saying same-sex couples are excluded from marriage,” Taylor says. “Some went further and said their public policy forbids any sort of same-sex accommodation.” (Illinois was one.) These states don’t need DOMA to take a stand.

One way to think of civil union is as a bundle of reciprocal legal contracts that otherwise a couple would have to negotiate and notorize one at a time—a stack of documents that would stuff a briefcase. That’s not the complete picture because with civil union come statutory marital rights no attorney could draw up, such as the spousal privilege in court. But as for those rights that can be asserted on paper, Lambda Legal advises couples in civil unions to get the paper anyway. “It’s more risky for people to rely on civil union than to rely on documents drawn up by a lawyer that don’t turn on the legal relationship of the two adults,” says Taylor.

And even that might not be enough. Taylor told me the story of Janice Langbehn, who a couple years ago was boarding a cruise ship in Miami with her partner, Lisa Pond, and their three children, when Pond was struck by an aneurism. She was pronounced dead hours later in a Miami hospital that wouldn’t allow Langbehn by her side, even after Langbehn presented the hospital with the document establishing that she had health care power of attorney. “You’re in an antigay city in an antigay state,” Langbehn says a social worker told her.

Langbehn eventually got five minutes with Pond, at the insistence of the priest administering the last rites. Lambda Legal later sued the hospital and lost, the hospital taking the position that health care power of attorney was one thing, visitation rights another.

This brings me back to the most curious of the benefits of the civil union bill.

An Illinois couple united in a civil union will be issued a certificate that an alien jurisdiction might choose to dismiss as a meaningless piece of paper. But if that couple breaks up, they’ll have to it the same way married couples do—in court. A divorce is no mere piece of paper. It’s a court decree, and it commands respect.

So the ultimate blessing of a civil union may be the opportunity to get a court-ordered divorce.

Full of stories, Taylor told me about a couple other court cases. The first comes with no names attached—only initials. AB and HL are women who met in 1984 and entered a relationship. In 1993 HL was artificially inseminated, that December she gave birth, and for the next year and a half both women were, in the words of Illinois Appellate Court, “equally involved” in the care of the infant, CBL. But in 1995 the relationship ended. HL moved to Chicago with CBL and denied AB any further contact with their child. AB sued for visitation rights, arguing that the facts established her as a “common law de facto parent.”

A judge dismissed the petition, and an appellate court agreed. The panel of three appellate judges explained, with perhaps a note of rue, that common law had been superseded by the new Illinois Marriage and Dissolution of Marriage Act. The act “expressly provided for visitation for non-custodial parents,” the court wrote, and later amendments laid out in minute detail the conditions of visitation for grandparents, great-grandparents, siblings, and stepparents. The law was so “detailed and comprehensive” that the court had no choice but to interpret it as the exact wishes of the Illinois legislature. “This court is not unmindful of the fact that our evolving social structures have created non-traditional relationships,” the court wrote. “This court, however, has no authority to ignore the manifest intent of our General Assembly. Who shall have standing to petition for visitation with a minor is an issue of complex social significance. Such an issue demands a comprehensive legislative solution. That solution is provided, by our General Assembly.”

That’s what can happen to you when there’s no divorce. And the civil union act must be understood as the General Assembly’s new solution. In a civil union, AB would have been just as much a parent as HL; when the split-up came she’d have been due the visitation rights (and all the other rights) of any divorced mate.

The other case Taylor told me about is just as unhappy a story, but it shows what can happen when the parent denied access to the child has some law on her side. In 2000 two Virginia women, Lisa Miller and Janet Jenkins, were united in a civil union in Vermont. In 2002 Lisa Miller-Jenkins gave birth, through donor insemination, and the couple moved to Vermont. A year later they split up. Lisa Miller-Jenkins and the child returned to Virginia, a state that had never recognized the civil union in the first place.

Lawyers advise parents in same-sex marriages or civil unions to take out adoption papers on their children, because of the danger their parental rights won’t be recognized in another state. Janet hadn’t done this. So perhaps Lisa’s big mistake was to file paperwork asking a Vermont family court to dissolve the civil union. That got a Vermont court involved.

A few weeks later Janet filed a counterclaim. Each woman asked for custody of little Isabella and offered visitation rights to the other. But over time Lisa’s position became more extreme: she wanted to make the point in court that Janet was actually no parent at all, not having any biological tie to Isabella and not having formally adopted her. The judge would have none of it—as he read the Vermont civil union law, Janet was as presumptively the parent as she would have been had she and Lisa been married.

I’m drawing on a lengthy discussion of Miller-Jenkins v. Miller-Jenkins that ran in 2007 in the Washington Post. The case became what the Post called an “ideological cause,” in which lawyers affiliated with Jerry Falwell and a counselor who teaches that lesbianism can be unlearned rallied to Lisa’s side.

In 2004 the saga reached its watershed: Virginia’s Marriage Affirmation Act became law, denying marriage or anything resembling marriage to same-sex couples and asserting such unions established in other states “void in all respects in Virginia,” all contractual rights established by such unions “void and unenforceable.”

The new law inspired Lisa to file a motion in Virginia asking the court to declare Janet’s claims on the child “void, illegal and/or unenforceable.” When the judge in Vermont heard about this he asserted tartly that the case was his and he had no intention of deferring to another state. He threatened Lisa with loss of custody.

A circuit judge in Virginia ruled in Lisa’s favor. Janet appealed, arguing among other things that Vermont had the case first so it should be decided there. The judge in Vermont ruled that the Virginia judge’s ruling was of no consequence because it was not his case. Lisa appealed, and Vermont’s supreme court ruled for its state’s judge. And two years after it got the case, a three-judge panel of the Virginia court of appeals also ruled for Janet: even though rights were involved that Virginia didn’t recognize, the Virginia judges unanimously agreed that the case belonged to Vermont.

Last month the Vermont supreme court awarded Janet sole custody of her daughter and the U.S. Supreme Court declined to hear Lisa’s appeal. Unfortunately for Janet, Lisa had disappeared with eight-year-old Isabella at the beginning of this year.

The hectoring Defense of Marriage Act doesn’t stop at merely urging states to disregard one another’s laws. It also advises them to disregard one another’s court rulings, something that as we’ve just seen, state courts are reluctant to do.

According to DOMA, no state—not to mention “territory, or possession of the United States, or Indian tribe”—need “give effect to any public act, record, or judicial proceeding of any other State, territory, possession, or tribe respecting a relationship between persons of the same sex that is treated as a marriage under the laws of such other State, territory, possession, or tribe, or a right or claim arising from such relationship.” The circuit judge in Virginia who heard Lisa’s motion was willing to give the Vermont proceedings no effect. The Virginia appellate court wasn’t.

Camilla Taylor believes DOMA is unconstitutional, and she likes to think that legal challenges now making their way through the courts will eventually show that. “To the extent it says the states don’t have to give respect to court decrees, it violates the equal protection clause and the due process clause,” she said. “It’s saying the state courts can ignore the full faith and credit clause of the constitution. It targets a minority for special and unfavorable treatment.”

What does the other side say? Champions of DOMA like to focus on tradition and morality, but these can be the basis of a constitutional argument. Consider the latest defense brief in Perry v. Schwarzenegger, the suit against the Proposition 8 ballot initiative that in 2008 outlawed same-sex marriage in California. (Oral arguments before a panel of federal appellate judges were heard December 6.) “The scope of fundamental due process rights is determined by this Nation’s history, traditions, and legal practices,” the brief argues, and all of these tie marriage to its “procreative purposes,” even though “the right to marry . . . does not inquire into fertility on a case-by-case basis.” As for gays and lesbians deserving special consideration under equal protection law—for that, homosexuality would have to be defined as “immutable,” which it has not, and homosexuals as “politically powerless.” The latter is clearly no longer true, says the brief, and had it been written in the past few days instead of a few weeks ago, it might have cited Illinois’s new civil union act as evidence.

Yet if the passage of the Illinois law shows political power, it also shows that power’s limits. To get around defenders of old-fashioned marriage its authors felt they had to create a legal status that the federal government and most states won’t recognize anyway.

Taylor points out a feature of the Illinois law she thinks could prove handy, given the general hostility to gay unions. “It’s a consent-to-jurisdiction provision,” she says. Any civil union entered into in Illinois remains under the jurisdiction of Illinois courts even if the couple leaves the state, and it can be dissolved under Illinois law. That’s nice to know if you’re an estranged couple stuck somewhere that never recognized your union in the first place.

And so Illinois has added to its lifestyle menu a consensual-relations choice that offers many of the benefits of marriage, but without mussing marriage’s hair, and all the benefits of divorce. What’s not to like?