Reactions to Bill Cosby's recent criticisms of some counterproductive ghetto behavior patterns have ranged from applause from some in the black audience that heard him to a cheap attack from white liberal Barbara Ehrenreich in the New York Times. "Billionaire bashes poor blacks" is the way Ms. Ehrenreich puts it.

Over the years, Bill Cosby has poured enough of his efforts and money into advancing blacks that he does not need any lessons from Barbara Ehrenreich on how to help his own people. But her attempts to pose as a friend and defender of blacks has implications that reach far beyond this one silly woman.

According to Ms. Ehrenreich, "it's so 1985 to beat up on the black poor." Among her other radical chic comments is, "it must be fun to beat up on people too young and too poor to fight back or the elderly rich wouldn't do it."

This is just one of innumerable ways that the political left evades criticisms -- whether of young thugs or schoolteachers or anyone else -- by simply calling the criticism "bashing" and shifting the focus to the supposedly bad motives of those who criticize.

"Friends don't let friends drive drunk," a slogan says. You don't let anybody you care about destroy himself without warning him. Those who want to exempt blacks from criticism are not friends.

Criticism is part of the price of progress. Economics professor Walter Williams has said that a turning point in his education -- and his life -- came when a schoolteacher in the Philadelphia ghetto chewed him out for wasting his abilities on adolescent nonsense.

The criticism hurt -- and there was no Barbara Ehrenreich there to defend him. So he turned his life around.

My own moment of truth came when a roommate at Harvard said to me one day: "Tom, when are you going to stop goofing off and get some work done?"

Goofing off! I didn't know what he was talking about. I thought I was working hard. But, when the midterm grades came out -- two D's and two F's in my four courses -- it became painfully clear that I was not working hard enough. I was going to have to shape up or ship out -- and I didn't have anywhere to ship out to.

I had been on my own for years and had gone into debt in order to go to Harvard. Moreover, there was no Barbara Ehrenreich to defend me. So I got my act together and graduated with honors.

Today, how many white schoolteachers are going to chew out some ghetto youth? How many white college students are going to tell a black roommate to stop goofing off?

In today's climate, too many teachers think they are doing black students a favor by feeding them grievances from the past and telling them how they are oppressed in the present -- and how their future is blocked by white racism. These are the kinds of friends who do more damage than enemies.

Why endure all the hard work, self-discipline and self-denial that a first-rate education requires if The Man is going to stop you from getting anywhere anyway? People who have been pushing this line for years are now suddenly surprised and dismayed to discover that many black students across the country regard academic striving as "acting white."

Many young blacks likewise regard speaking correct English, or even observing the rules of polite society, as "acting white." White liberals often cheer them on in their self-destructive behavior or at least "understand" them and defend them.

Blacks have, in effect, been adopted as mascots by many white liberals. Mascots serve to symbolize something for others but the actual well-being of the mascot himself is seldom a major concern. Blacks have long been used by the left to indict American society.

People like Barbara Ehrenreich get their jollies saying clever things to needle American society, whether on race or other issues. The actual consequences of their liberal vision for blacks themselves get remarkably little attention.

So what if the social pathologies in the black community grew far worse after liberal doctrines became government policies in the 1960s? The vision is what matters to the left -- and the opportunities it presents for them to be clever with words.