For most of Western history, marriage was a matter of private contract between the betrothed parties and perhaps their families. Following that tradition, marriage today should be a private arrangement, requiring minimal or no state intervention. Some religious or secular institutions would recognize gay marriages; others would not; still others would call them domestic partnerships or assign another label. Join whichever group you wish. The rights and responsibilities of partners would be governed by personally tailored contracts — consensual bargains like those that control most other interactions in a free society.

Regrettably, government has interceded, enacting more than 1,000 federal laws dealing mostly with taxes or transfer payments, and an untold number of state laws dealing with such questions as child custody, inheritance and property rights. Whenever government imposes obligations or dispenses benefits, it may not “deny to any person within its jurisdiction the equal protection of the laws.” That provision is explicit in the 14th Amendment to the U.S. Constitution, applicable to the states, and implicit in the Fifth Amendment, applicable to the federal government.

Of course, government discriminates among its citizens all the time. By the 1920s, 38 states prohibited whites from marrying blacks and certain Asians. Until 1954, all states were allowed to operate segregated schools. Thankfully, the Supreme Court invalidated both interracial marital restrictions and school segregation. The court applied the plain text of the Equal Protection Clause despite contrary practices by the states for many years even after the 14th Amendment was ratified in 1868.

To pass constitutional muster, racial discrimination had to survive “strict scrutiny” by the courts. Government had to demonstrate a compelling need for its regulations, show they would be effective and narrowly craft the rules so they didn’t sweep more broadly than necessary. That same regime should apply when government discriminates based on gender preference.

No compelling reason has been proffered for sanctioning heterosexual but not homosexual marriages. Nor is a ban on gay marriage a close fit for attaining the goals cited by proponents of such bans. If the goal, for example, is to strengthen the institution of marriage, a more effective step might be to bar no‐​fault divorce and premarital cohabitation. If the goal is to ensure procreation, then infertile and aged couples should be precluded from marriage.

Instead, most states have implemented an irrational and unjust system that provides significant benefits to just‐​married heterosexuals while denying benefits to a male or female couple who have enjoyed a loving, committed, faithful and mutually reinforcing relationship over several decades. That’s not the way it has to be. Government benefits triggered by marriage could just as easily be triggered by other objective criteria, leaving the definition of marriage in the hands of private institutions.

For instance, the Senate Homeland Security and Governmental Affairs Committee recently voted to extend employee benefits to same‐​sex partners of federal employees. The qualifying criterion, which could also apply to heterosexual couples, is an affidavit identifying the domestic partner and certifying that the partnership is intended to be exclusive and permanent, within a common residence, with shared responsibilities.

Similarly, some states dispense benefits to qualifying gay couples joined in predefined civil unions. Even private‐​sector employers are increasingly offering same‐​sex “marital” benefits. According to the federal Office of Personnel Management, nearly 60% of Fortune 500 companies confer employment benefits on domestic partners.

Yet our politicians, unwilling to privatize marriage, seem congenitally unable to extricate themselves from our most intimate relationships. One would hope, in the coming months and years, that more enlightened federal and state legislators will have the courage and decency to resist morally abhorrent and constitutionally suspect restrictions based on sexual orientation. Gay couples are entitled to the same legal rights and the same respect and dignity accorded to all Americans.