A central question in the legal debate over the constitutionality of laws that discriminate against gays and lesbians (such as the federal Defense of Marriage Act) turns on the appropriate standard a court should apply in deciding whether the government's interest in treating gays and lesbians differently from other Americans is sufficiently weighty to justify the discrimination.
The Equal Protection Clause of the Fourteenth Amendment, which provides that no state shall deny any person "the equal protection of the laws," is the relevant constitutional text. But what does it mean?
A simple interpretation might suggest that the government may never treat people differently. But that is an implausible understanding of the text. All laws treat people differently. Speed limit laws treat people who drive 75 miles per hour differently than those who drive 45 miles per hour. People who have gone to medical school can practice medicine; others cannot. Citizens can vote; aliens cannot. In-state college students pay a lower tuition than out-of-state college students. People over 65 receive certain benefits that are not available to people under 65. And so on.
Surely, the Equal Protection Clause cannot mean that all such laws are unconstitutional. Recognizing this, the Supreme Court has held that most laws that treat some people differently from others are constitutional if the difference in treatment rationally furthers a legitimate government interest. As illustrated by the examples noted above, almost all laws pass this test.
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