The Supreme Court’s predictable 5-4 vote to reverse the decision by Judge Sonia Sotomayor and two federal appeals court colleagues against 17 white (and one Hispanic) plaintiffs in the now-famous New Haven, Conn., firefighters decision does not by itself prove that the Sotomayor position was unreasonable.

After all, it was hardly to be expected that the five more conservative justices — who held that the city had violated the 1964 Civil Rights Act by refusing to promote the firefighters with the highest scores on a job-related promotional exam because none were black — would endorse an Obama nominee’s ruling to the contrary.

What’s more striking is that the court was unanimous in rejecting the Sotomayor panel’s specific holding. Her holding was that New Haven’s decision to spurn the test results must be upheld based solely on the fact that highly disproportionate numbers of blacks had done badly on the exam and might file a "disparate-impact" lawsuit — regardless of whether the exam was valid or the lawsuit could succeed.

This position is so hard to defend, in my view, that I hazarded a prediction in my June 13 column: "Whichever way the Supreme Court rules in the case later this month, I will be surprised if a single justice explicitly approves the specific, quota-friendly logic of the Sotomayor-endorsed… opinion" by U.S. District Judge Janet Arterton.

Unlike some of my predictions, this one proved out. In fact, even Justice Ruth Bader Ginsburg’s 39-page dissent for the four more liberal justices quietly but unmistakably rejected the Sotomayor-endorsed position that disparate racial results alone justified New Haven’s decision to dump the promotional exam without even inquiring into whether it was fair and job-related.

Justice Ginsburg also suggested clearly — as did the Obama Justice Department, in a friend-of-the-court brief — that the Sotomayor panel erred in upholding summary judgment for the city. Ginsburg said that the lower courts should have ordered a jury trial to weigh the evidence that the city’s claimed motive — fear of losing a disparate impact suit by low-scoring black firefighters if it proceeded with the promotions — was a pretext. The jury’s job would have been to consider evidence that the city’s main motive had been to placate black political leaders who were part of Mayor John DeStefano’s political base.

Disparate-impact law, as codified by Congress in 1991, specifies that an employer whose qualifying exam or other selection criterion produces racially disparate results can be held liable for unintentional discrimination only if (1) the test is not "job-related… and consistent with business necessity," or (2) the employer is presented with and refuses to adopt another, similarly job-related test with less disparate impact.

Contrary to the Sotomayor-endorsed opinion, the Ginsburg dissent states (on page 19) that an employer’s decision to jettison a promotional test under circumstances like this case would be legal only if the employer had "good cause to believe the [test] would not withstand examination for business necessity."

Ginsburg added (on page 26 and page 33) that "ordinarily, a remand for fresh consideration" would be proper because the lower courts (including Judge Sotomayor) had not carefully considered the evidence of "pretext" and racial politics.

To be sure, Justice Ginsburg also found (against the clear weight of the evidence, in my view) that New Haven did have good cause to believe that the test was invalid. She also said that if ether party was to be granted summary judgment, it should have been the city, and that the Supreme Court majority had erred in awarding summary judgment to the high-scoring plaintiffs.

But as a matter of law, the difference between the Sotomayor position and the Supreme Court dissenters’ position is nonetheless important and revealing.

Both, in my view, would risk converting disparate-impact law into an engine of overt discrimination against high-scoring groups across the country and allow racial politics and racial quotas to masquerade as voluntary compliance with the law.

But while Ginsburg at least required the city to produce some evidence that the test was invalid, the Sotomayor panel required no such evidence at all. Its logic would thus provide irresistible incentives for employers to abandon any and all tests on which disproportionate numbers of protected minorities have low scores.

And racially disparate scores on virtually all objective tests are unfortunately the norm, not the exception. It’s not hard to understand why: Studies have long showed that because of unequal educational opportunities and cultural differences, the average black high-school senior has learned no more than the average white eighth-grader — and considerably less than the average white senior.

Of course, this would be no justification for basing promotions on test scores that have little relationship to the requirements of the job. But the New Haven exam was clearly job-related and carefully developed to insure race-neutrality, as the majority opinion of Justice Anthony Kennedy detailed.

To be sure, as Ginsburg argued, alleged imperfections in the New Haven test were attacked by black firefighters, city officials, and others after the fact. But every written and oral objective test ever devised can be similarly attacked as imperfect. If the law were as Judge Sotomayor ruled, no employer could ever safely proceed with promotions based on any test on which minorities fared badly.

The broader questions lying behind the New Haven case are whether this nation will ever get beyond racial preferences and quotas such as those encouraged by both the Sotomayor and the Ginsburg positions, and whether it will ever realize Dr. Martin Luther King’s dream of a nation where people are judged not by the color of their skins, but by the content of their characters.

Justice Ginsburg’s prediction that the New Haven decision "will not have staying power" seems to reflect a conviction that the nondiscrimination ideal articulated by Dr. King should be put on hold for the indefinite future, if not forever. Judge Sotomayor’s position in the case, and some of her off-the-bench pronouncements, suggest the same even more strongly.

President Obama’s campaign rhetoric about getting away from identity politics and racial spoils seemed to promise something rather different.