In a recent speech to the National Rifle Association, John McCain presented himself as an advocate of judicial restraint. The presumptive Republican presidential nominee decried "activist judges" who override the will of the people as expressed by their legislative representatives, in the process "shrugging off generations of legal wisdom and precedent."

Yet that is exactly what the U.S. Supreme Court will be doing if, as the Arizona senator urges, it overturns the District of Columbia's gun ban. Evidently some kinds of judicial activism are better than others. Perhaps activism vs. restraint is not the best measure of what makes a good judge.

The most recent Supreme Court decision addressing the Second Amendment is ambiguous but has often been read as an endorsement of the view that "the right to keep and bear arms" pertains only to state militia service. That is the position taken by most federal appeals courts, and until relatively recently it was the conventional wisdom among legal scholars.

McCain nevertheless is right that the Supreme Court should reject that view -- not because doing so epitomizes judicial restraint but because a thorough examination of the Constitution and its historical context shows that view is wrong. It is wrong no matter how many legislators, academics and judges have endorsed it, no matter how long it was widely accepted.

What about the California Supreme Court's conclusion, announced the day before McCain's speech, that the state constitution requires official recognition of same-sex marriages? McCain criticized the ruling for overriding the people's will, reflected in a 2000 ballot initiative that reaffirmed the traditional definition of marriage as a union between one man and one woman. Although the four judges in the majority acknowledged their decision was inconsistent with the way marriage had always been understood under state law, they argued that long acceptance does not make a policy constitutional.

To buttress that point, they cited the 1948 decision in which the California Supreme Court overturned a ban on interracial marriage that had been in place since 1872. But that decision was based on the 14th Amendment, which was passed after the Civil War with the aim of guaranteeing the residents of every state, regardless of race, the "privileges or immunities of citizens," "due process of law" and "equal protection of the laws."

It was not much of a stretch to conclude that the 14th Amendment, which the U.S. Supreme Court had said protected "the right of the individual ... to marry," barred anti-miscegenation laws. By contrast, the California Supreme Court now is redefining that right to mean something it never has meant, treating two people of the same sex, as opposed to a man and a woman of different races, as "similarly situated" and therefore entitled to identical treatment in the name of equal protection.

As a matter of policy, I favor an arrangement similar to the one mandated by the court, in which the government treats couples equally without regard to sexual orientation. The California legislature already has done that in almost every respect, extending to gay "domestic partners" all the rights and responsibilities that apply to heterosexual couples under state law, while withholding the "marriage" label.

So why does it matter if a court pushes the state a bit further in this direction, requiring equal nomenclature as well as equal treatment? Because the state constitution leaves that decision to the legislative process, and a constitution that can be ignored to reach good results also can be ignored to reach bad results.

As McCain noted in his NRA speech, many gun control advocates claim the Second Amendment is "archaic," no longer relevant in modern America. Advocates of campaign finance regulation, including McCain himself, argue that the contemporary threat of big money in politics requires revising the First Amendment's command that "Congress shall make no law ... abridging the freedom of speech." For courts confronted by laws based on such constitutional revisionism, judicial restraint is no virtue.