It’s not often that David Letterman lets his viewers behind his wise-ass veil to see the salt-of-the-earth Midwestern guy he really is. His first post-9/11 monologue was one example. More recently, his peacemaking with Mary Hicks—mother of the late, great comic Bill Hicks—showed Letterman to be a real mensch, contrite for a wrong committed more than 15 years before.

The controversy between Letterman and Hicks is the stuff of comedy legend. Hicks had appeared on Letterman’s show many times, always funny, sharp, and sometimes a little edgy. But on October 1, 1993, what would have been Hicks’ last appearance was thought to be too edgy, and got cut—reportedly the only performance ever removed from Letterman’s show.

On January 30, 2009, that performance finally aired.

Hicks died of pancreatic cancer not long after that unfortunate episode, on February 26, 1994, exactly 15 years ago. He called himself “Chomsky with dick jokes,” and spoke of spirituality and embracing humanity like a New Age guru (an option kyboshed by his legendary love of cigarettes and booze). But he showed no patience for obnoxious, dim-bulb audiences. Fans love that about him.

It is a great testament to Bill Hicks that he is still respected by his fellow comics and revered by discerning comedy fans. His CDs and DVDs still fly off the shelves. Several biographies and compilations of his material have been published, he’s been the subject of academic research, tributes are held in his honor, and Hicks goods are a cottage industry.

The question is, why? Why is Bill Hicks so popular today when he never got the recognition his talent demanded during his lifetime? Sure, he was and remains something of a demigod in the U.K., but American audiences never gave him his due, while lesser comics found unmitigated success. (As biographer Cynthia True noted in American Scream, a week after Hicks died, Carrot Top received an American Comedy Award.)

Maybe his timing was off. Not his comedic timng—that was always impeccable. But being a political comic with a sharp leftist bent was not safe or convenient in the Reagan/Bush years when Hicks’ star was on the ascent.

His appreciation for drug use—encouraging those willing to open their minds and just say yes—was off kilter with a nation pledged to “just say no.” He asked why TV news never covers “positive drug stories”:

“Today, a young man on acid realized that all matter is merely energy condensed to a slow vibration and that we are all one consciousness experiencing itself subjectively. There’s no such thing as death, life is only a dream, and you are the imagination of yourself. Here’s Tom with the weather!”

When Gordon Gekko was telling America that greed is good, and Americans were believing it—continuing unto our current nightmare—Hicks was reminding his audience that the ability to buy and sell things is no measure of success.

And long before President Obama made America post-racial (*wink*), maybe Hicks’ take on race relations, vis-à-vis the Rodney King riots, was too discomforting to mainstream audiences.

San Francisco-based comic and playwright Kurt Weitzmann says Hicks’ comedy was an act of courage in the Reagan years.

“Hicks was fearless in stating his point of view. When you’re telling jokes to a room full of strangers in a comedy club, trying to make them laugh with a definite political slant that usually goes against the belief structure of a good half of the room, your logic must be rock solid and your jokes must be brilliant. His act was both rock solid and brilliant,” Weitzmann says.

Yet despite the difficulty in getting his message into the mainstream, Hicks maintains and even expands his fan base. And his effect on other comics continues. Kevin Kataoka, a very clever and highly successful comic in his own right, says his early contacts with Hicks provided a foundation for his career that followed. “He praised my ‘bad ventriloquist’ joke that I treasure for that reason,” Kataoka says. “He made me realize that he didn’t want my act to mimic his—something comics don’t get—but to be honest to what makes you truly unique and funny.”

Perhaps the most compelling evidence of Hicks’ brilliance is the staying power of much of his material. “My political jokes are old in two weeks. Hicks’ stand up after 15 years,” says Tina Dupuy, a Los Angeles-based comic and writer. “He hasn’t told a joke since the Lorena Bobbit case, and still no one can follow him.”

Dupuy’s position finds ample proof all over the internet. Gays in the military still an issue? Rush Limbaugh said some stupid and inflammatory jackass thing for no good goddamn reason? New Kids on the Block are selling gutless, soulless pop to adoring fans (again!) while music that matters is pushed to the margins? The U.S. military is plodded down in the desert somewhere, making war on people we claim to be helping? Hicks’ material is still relevant, still on target, and still hard-hitting. And funny.

But Hicks’ brilliance goes beyond taking the day’s news and spinning it into comedy gold. Like Kataoka says, it has to do with being honest with yourself and with your audience, being true to your reality and letting the humor come from that naked place. Hicks did that. And beyond honesty, he committed to it with love.

Bill Hicks was 32 when he died. That just feels wrong.