Silence treatment.

Want to experience intimidation on the job? Just speak out against preferences.

Back in the 1930s and 1940s, the NAACP found it difficult to enlist black teachers to serve as plaintiffs in its salary-equalization suits because the teachers were likely to get fired. In 1955, the head of the Dallas County White Citizens Council reported that the council had prompted the firing of 16 out of 29 blacks who had petitioned the city board of education in Selma, urging school integration. Today these methods of intimidation are back, but in the service of a dramatically different cause.

Edward Blum, Larry Elder, and John Carlson are thoughtful, principled men joined by two things: 1) they all believe that people should be judged as individuals, not by their race; 2) they all personally suffered on the job for taking that position. Their employers bowed to strong-arm tactics of preference advocates designed to stifle their employees' free expression. The experiences of these three men demonstrate how powerful political correctness still is, and how susceptible corporate America is to intimidation on racial matters.

Blum is chairman of the Campaign for a Color-Blind America, an organization that challenges race-based public policies. Since 1993, the Campaign has been on the winning side of lawsuits challenging racially gerrymandered voting districts and race-based admission policies in public colleges. Most recently, it ran the campaign for ''Proposition A,'' a ballot initiative that sought to ban Houston's use of race preferences.

Blum's advocacy so upset then-mayor Bob Lanier that Lanier reportedly called Blum's bosses at Paine Webber and threatened to discontinue the firm's contracts to underwrite city bonds. Expansively interpreting its corporate policy requiring employees to submit any investment-related articles for official approval before publication, the firm demanded that Blum cease his public statements against preferences.

In a written reprimand, Paine Webber told Blum his work outside the firm created an ''adverse perception of the firm, resulting in the firm's loss of certain municipal underwriting business. . . . You are advised that the firm will not clear for publication articles or other press contacts in which you espouse an anti-affirmative action position. . . . Any further violations of the firm's corporate communications policy, or any other firm policies, will result in your immediate termination from the firm.''

Rather than submit, Blum left Paine Webber and joined an investment firm that permits him to continue his work against preferences. He got more good news on June 26, 1998, when District Judge Sharolyn Wood invalidated the results of the Houston referendum, ordering a new election. Over the objections of the measure's sponsors, the mayor and city council had reworded the initiative so as to cast it in the most negative light possible. The court's decision requires Houston to hold another election using Proposition A's original language, which Blum crafted.

WHEN Larry Elder's radio talk show on KABC-AM in Los Angeles was cut in half from its usual four hours, a secret group called ''Talking Drum,'' which threatened a boycott against Elder's sponsors, claimed victory. Elder is a champion of free and open discussion -- he goes out of his way to invite on the air people who disagree with his opposition to preferences. But as the Los Angeles Times Magazine wrote in a recent cover story on Elder, ''This vigorous intellectual voice, buffed for verbal combat, cannot seem to find a worthy opponent. His enemies do not want to play.''

Members of the civil-rights elite and representatives from ''Talking Drum'' continue to avoid him rather than engaging in public discourse on issues of race. However, thanks to his popularity among listeners, Elder eventually prevailed. Not only did he regain his full time slot, but his show will soon be nationally syndicated.

John Carlson can sympathize. As chairman of Washington State's ''Initiative 200'' campaign, Carlson got more than 280,000 Washington residents to sign petitions supporting this anti-preference measure. Like Elder, Carlson actively sought out his opponents and gave them air time during his radio program, which Seattle's KVI-AM had carried for more than five years. When I-200 opponents gathered outside his studio for a Martin Luther King Day rally, he invited their leaders in to talk.

Faced with polls showing more than 60 per cent of Washington voters supporting I-200, preference advocates weren't so open-minded. Applying the same techniques that had been used against Elder and Blum, they undertook a campaign of misinformation -- centered on a confusing alternative initiative -- because, as Edsonya Charles, treasurer of ''No 200,'' admitted, ''Confusion helps us and hurts the supporters of I-200.''

After initially giving Carlson the green light to head the initiative drive -- the third time he had led an initiative campaign since joining KVI in July 1993 -- station executives in December ordered him to stop talking about it. And in February, KVI fired him because he disobeyed the earlier order and continued talking about I-200 -- a hot topic not only for his listeners, but for all media in the state. The following weekend, KVI erased from its website the hundreds of e-mails expressing outrage at Carlson's dismissal.

As of June, however, John Carlson is back, this time in cyberspace. On www.talkspot.com, Carlson now takes e-mails rather than phone calls. And he continues to support I-200. As he says, ''My departure from KVI does not shrink this debate [on preferences]. It expands this debate. And the more it's debated, the better.'' If only supporters of preferences felt the same way.

Mr. Mellor is president and general counsel for the Institute for Justice, based in Washington, D.C.