The last liberal lion is on the hunt again. Judge Stephen Reinhardt of the Ninth Circuit Court of Appeals, the judge who struck down California's Proposition 8, has issued an opinion holding that equal protection is violated when a lawyer uses a peremptory strike to keep a gay juror out of a case. In so holding, Reinhardt formally maintained that, under the Supreme Court's decision in U.S. v. Windsor, gay people are entitled to heightened scrutiny from the courts when they are subjected to differential treatment.

The decision, SmithKline Beecham v. Abbott Laboratories, is both a landmark and an invitation for Supreme Court review. It poses one of the most fascinating and fundamental questions to arise in the wake of the court's gay marriage decision: Do gay people require special protection from the courts? Or does the historic decline of homophobia prove that profound discrimination against gay people is over?

The case arose out of an ordinary suit between two big pharma companies, GlaxoSmithKline Plc and Abbott Laboratories, over the alleged gaming of the sale of an anti-HIV drug. In the run-up to the trial, Abbott used its first peremptory strike against a jury member who referred several times in voir dire to his partner, using the masculine pronoun.

Ordinarily, the peremptory strike is the free shot of the jury process. It can be exercised without giving a reason -- so long as the unspoken reason isn't discrimination. The Ninth Circuit, the first court to do so, held that it must subject Abbott's use of the challenge to "heightened scrutiny" because it was exercised against a gay person. The apparent motivation for the strike was the assumption that a gay juror might not be sympathetic to a company that was accused of trying to raise the price of anti-HIV medications to pad its corporate coffers.

In general, the law of equal protection says that ordinary laws or government decisions must only be subject to a modest and minimal review that ascertains they have been taken on a "rational basis." That is, absent some form of prohibited discrimination, the courts ordinarily take only a brief and forgiving look at what the government has done.

So-called "heightened scrutiny" by the courts happens when the classification drawn by the government deserves to be treated with suspicion. Classifications that differentiate between blacks and others are the classic example of where the highest form of heightened scrutiny, called "strict scrutiny," is appropriate. The Supreme Court has long held that, because blacks form a "discrete and insular" minority group subject to historical discrimination, the courts must look especially carefully at situations where the government has treated them differently, and must ascertain with the greatest degree of care whether they have been subject to unlawful discrimination. Laws that differentiate based on sex do not get quite as careful a look, but they do get a form of heightened scrutiny sometimes called "intermediate scrutiny," because women, too, have historically been subject to discrimination.

In practice, what all this technical jurisprudence means is that it's extremely hard for a government to get away with discriminating against blacks, and it's pretty hard to discriminate against women, too. Strict scrutiny is usually fatal to a government decision, and intermediate scrutiny is not far behind. In layman's terms, blacks and women get special protection.

Reinhardt's decision for the Ninth Circuit extends a version of this special protection to gay people. The 82-year-old Reinhardt, a President Jimmy Carter appointee (yes, you read that right), is by common consensus the most assertive, activist liberal judge in the U.S. In complete control of his formidable intellectual powers, he has for many years refused the senior status that would allow him a reduced workload at full pay.

To liberals, the politically sophisticated Reinhardt is the last of the just, a Warren Court activist who has by sheer stubbornness survived into the age of Chief Justice John Roberts. To conservatives, Reinhardt is anathema, a devious tactician who never sleeps in the course of his ceaseless efforts to bend the Constitution and the laws to achieve his left-liberal ends. Whether openly or secretly, both sides revere him, and most everybody wishes he would keep at it forever, whether their goal is to laud him or condemn him to the fiery pit.

As a master legal craftsman, Reinhardt argued that not he but the Supreme Court in its Windsor decision demanded heightened scrutiny for differential treatment of gays. How else, he asked, could the Supreme Court have evaluated the motives of the Defense of Marriage Act so searchingly, if not by exercising heightened scrutiny? This argument perversely echoed the attitude of the Windsor dissenters, including Justice Antonin Scalia, who denounced the opinion as so much "legalistic argle-bargle" in part for failing to be clear about its rationale. In arguing that the opinion made no sense except as an exercise in heightened scrutiny, Reinhardt exploited Justice Anthony Kennedy's very obvious and doubtless intentional approach of never explaining whether he was applying heightened scrutiny in the first place.

All of which raises the most fundamental question of all: Now that gay marriage is gaining traction in the courts and public opinion, and homophobia is on the decline, should we categorize homosexuality under a constitutional standard developed to protect against racial discrimination? Reinhardt pointed to a history of anti-gay legislation and social practice, which certainly existed and in certain circles persists nationwide.

Yet compared with blacks and women, gay people have experienced astonishingly rapid progress toward equality. Racism still undergirds huge economic and social differences between whites and blacks, our first black president notwithstanding. Sexism keeps women from getting equal pay for equal work. Neither bias is on the edge of extinction. By contrast, dislike of gay people is, thank God, fading fast. Even Pope Francis seems to be in on the action -- and when the pope is pushing a nonjudgmental attitude toward gay people, you can pretty much accept that the jig is up for open homophobia, at least in the U.S.

It's a tricky question, but in the end, the answer is probably that Reinhardt went too far. Equality for gay people is a pressing imperative of civil liberties. But progress has been achieved so far without relying on a forced legal analogy to discrimination against blacks and women. Those forms of discrimination have structural economic roots that make them particularly persistent and pernicious. Homophobia, by contrast, is a nasty social attitude that can be eventually reduced to the point of this disappearance -- and when it is gone, gay people will be truly equal. That day is coming, with the help of the courts and common sense. Heightened scrutiny can be reserved for those people who really need it.

Noah Feldman, a law professor at Harvard University and the author of "Cool War: The Future of Global Competition," is a Bloomberg View columnist. Follow him on Twitter at @NoahRFeldman.