Whatever else might be said about Tiger Woods, he has never confused his ethnic and racial makeup — he is part Asian, part black, part American Indian, and part white — with his identity. “My parents have taught me to always be proud of my ethnic background,” he said as a 19-year-old US Amateur champion in 1995, but “the critical and fundamental point is that ethnic background and/or composition should not make a difference. It does not make a difference to me. The bottom line is that I am an American.”

Race didn’t turn Tiger Woods into a great golfer any more than it made him a serial philanderer, and it is hard to imagine anything less relevant to his current marital turmoil than skin color. Yet from the Associated Press comes a report headlined “Tiger’s troubles widen his distance from blacks” — an entire news story devoted to “the race of the women linked with the world’s greatest golfer.” Apparently they have all been white. Apparently some people think that matters.

It isn’t just the AP. Washington Post columnist Eugene Robinson suggested last week that “the most interesting aspect” of Woods’s humiliating fall is “the whole Barbie thing.” Robinson disavows any desire “to pronounce judgment on Woods’s moral fiber” — he would rather dwell instead on “how much the women who’ve been linked to Wood resemble one another” and why none of them have “yellow or brown skin.”

Is that really what matters in the Tiger Woods drama? Must everything be turned into a matter of race?

Few cultural ideas are more pernicious than the race fetish — the regard for skin color or ethnicity as the most significant factor in human behavior. Few falsehoods have caused more misery. If anything ennobled 20th-century liberalism, it was the conviction that human beings ought to be treated without regard to the hue of their skin or the shape of their eye. As Thurgood Marshall argued in a 1948 brief for the NAACP Legal Defense Fund, “Classifications and distinctions based on race or color have no moral or legal validity in our society.”

America’s greatest modern domestic achievement was to transform itself from a society in which invidious racial classifications were entrenched in law and custom — a society in which the “wrong” skin color was a bar to everything from decent schooling to political power — to one in which blacks can be anything: judges and entrepreneurs, journalists and lawmakers, billionaire golfers and four-star generals — and president of the United States.

Over the past two generations, in a blink of history’s eye, America changed from a nation in which the race card trumped nearly everything to one in which it trumps nearly nothing.

So why do so many people keep trying to play it?

When US Representative Artur Davis, an Alabama Democrat, voted against the House leadership’s health care bill last month, he was denounced in racial terms by members of his own party. “You can’t vote against health care,” Jesse Jackson told a Congressional Black Caucus reception, “and call yourself a black man.”

When posters appeared in which President Obama’s face was Photoshopped to resemble Heath Ledger’s creepy Joker from the Batman movie “The Dark Knight,” it was promptly slammed as racist. “All that’s missing is a noose,” wrote LA Weekly’s Steven Mikulan — despite the fact that Ledger was white, the Joker is white, and the poster’s one-word message was nonracial: “Socialism.”

Or is “socialism,” too, a matter of race? In an essay the Christian Science Monitor published in October, University of North Carolina professor Christopher Lee insisted that Obama’s critics use the S-word to disguise their true “xenophobic, hypernationalistic, and, yes, racist” views.

It is so odious, this impulse to make everything a racial matter. Whether it comes from right or left, whether the context is congressional legislation or celebrity gossip, the race card invariably diminishes and divides us.

“There is not a Black America and a White America and Latino America and Asian America,” declared Barack Obama at the 2004 Democratic National Convention. “There’s the United States of America.” True, we may not be there yet. But isn’t the surest way to an America in which race makes no difference to stop speaking and acting as if it does?