"Free Mumia," read the headline. The sign concerned efforts by the Uhuru Democratic Party, the local successor to the Black Panthers, to release the convicted murderer of Philadelphia police officer Daniel Faulkner from death row. Abu-Jamal killed Faulkner back in 1981, and a jury found him guilty only one year later. In the intervening seventeen years, however, left-wing supporters have waged a tireless campaign to exonerate their man. In April, thousands marched in Philadelphia to demand his freedom. Speakers at the rally included Ramsey Clark and Ossie Davis.

They are but two of the many celebrities on the Mumia bandwagon. Whoopi Goldberg, Ed Asner, Peter Coyote, Mike Farrell, punk-rock band Rage Against the Machine, and many others are also on board. The group is so eclectic that it’s difficult to see what it is that unites them around this particular murderer.

Well, ignorance, for one. Ed Asner once complained to Philadelphia Magazine that there were no African Americans on the jury that convicted Mumia. But Asner was wrong, there were two. In a December, 1998, broadcast of ABC’s 20/20 he claimed that police had performed no ballistics tests in their investigation. He was wrong about that, too.

Then there’s fanaticism. Rage Against the Machine’s website dedicates much space to the band’s egalitarian, utopian views, inveighing against capitalism, industry, and corporations—while they earn millions precisely because of those very institutions. For hard-core leftists, Mumia, (like Alger Hiss before him) is innocent, or at least the question of his guilt is irrelevant, because he is a comrade

Hatred is also largely to blame. The police, more than any other organization, represent government power. For those out to discredit American democracy or its laws, they make an easy and popular target. Some of Ramsey Clark’s other ventures into political activism have included participating in war-crimes trials against the US for its involvement in the Gulf War and representing the Iraqi government in the US. Various pro-Mumia organizations, such as MOVE, the African People's Socialist Workers Party, or the Uhuru Democratic Party routinely call for Communist revolution.

Last but not least, there’s racism. Many racial agitators see Bull Connors in every white police officer. Their knee-jerk reaction to a white cop shooting a black person is that the shooting is murder. All white officers are evil; all black criminals are innocent.

Even news of the murderer’s confession doesn’t seem to change their thinking. The pro-Mumia march in April, plus the undeserved invective that has been thrown in Mrs. Faulkner’s direction, recently prompted one of Mumia’s former confidants to speak out. Philip Bloch, a former volunteer with the Pennsylvania Prison Society and an opponent of capital punishment, is quoted in the August issue of Vanity Fair as saying that Mumia once privately expressed regret about killing Officer Faulkner.

Predictably, Mumia supporters have begun their character assassination. Pam Africa, head of International Concerned Family and Friends of Mumia Abu Jamal, and the murderer’s number-one fan, told the Philadelphia Daily News that Abu-Jamal would never confess to "some young white boy." With that one statement, Ms. Africa symbolizes the hatred, racism, and fanaticism that is typical of pro-Mumia activists. For them, truth is a small sacrifice to make for the Movement, as is the life of a police officer.

Whatever their reasons, Mumia’s advocates are as numerous as they are diverse. Their advocacy is also a shibboleth. The-left wing fanatics of America and the world are revealed by their endorsement of this cause. For that we owe them our gratitude.

We also should be grateful that they have exposed the complacency inherent in America’s institutions. There has been no substantial campaign to counter the distortions and propaganda proffered by Mumia’s proponents. No crusade to tell the truth about this case. The city of Philadelphia, its police department, its police officers’ union, its DA's office—none has chosen to respond to the fabrications. Because of their lack of response, elected officials in San Francisco, Madison, Wisconsin, and other cities have passed resolutions esteeming a murderer. In 1995, I attended a rally to uphold Mumia’s conviction. There were few Philadelphia police officers present. The lack of attendance is a sad commentary on the apathy of the average patrolman and citizen.

Only the widow of the murdered police officer mounted a counter effort—despite death threats by Mumia’s backers. But it has little following. Recently a Philadelphia talk-show host organized a fund-raising dinner to support her organization. So far, the impact seems to have been negligible. If the fanatics of the left achieve their goal of releasing a convicted murderer— and even with Philip Bloch’s testimony, they still might—it will be a direct result of mainstream American’s apathy, and its failure to heed the warning of Edmund Burke, that "The only thing necessary for the triumph of evil is for good men to do nothing."

Mr. Tremoglie is a former Philadelphia police officer, and now a health-care consultant and freelance writer living in Philadelphia.