Last week, the Vermont legislature overrode the governor to legalize gay marriage. The week before, the Iowa Supreme Court achieved the same result by overriding the state legislature, declaring a 1998 ban on same-sex marriage unconstitutional.

For those who agree (as I do) that the benefits of civil marriage should be available to all couples regardless of sexual orientation, does it matter how we get to that destination? I think it does, because the approach taken in Iowa, although liberty-enhancing in this case, ultimately undermines a constitution's ability to constrain government action and protect individual freedom.

The seven-member Iowa Supreme Court unanimously ruled that limiting marriage to heterosexual couples violates the state constitution's guarantee of equal protection, which it said "is essentially a direction that all persons similarly situated should be treated alike." It seems safe to say that neither the constitutional convention delegates nor the voters who approved this provision in 1857 would have agreed that two people of the same sex and two people of opposite sexes were "similarly situated" and "should be treated alike" under civil marriage laws.

In fact, that remains a minority opinion in Iowa. Last month, a University of Iowa survey found that only 26 percent of Iowans supported gay marriage.

The Iowa Supreme Court overrode the majority's view by reinterpreting the equal protection clause to mean something it did not mean when it was adopted. "Our responsibility," the justices explained, "is to protect constitutional rights of individuals from legislative enactments that have denied those rights, even when the rights have not yet been broadly accepted, were at one time unimagined, or challenge a deeply ingrained practice or law viewed to be impervious to the passage of time." Continued...