Judith Hanna is a lap dance expert.

She argues it's not just naked hotties doing the grind for their tipping customers. It is artistic expression on par with ballet.

She has a doctorate in anthropology from Columbia University. She is a senior research scholar in the departments of dance and anthropology at the University of Maryland. She is the author of several books and scholarly articles on dance forms from African folk to flamenco.

To advance her research, Hanna has had a few lap dances herself. She's been to more than 4,000 strip clubs to interview dancers, patrons, club owners and personnel. She's taken her husband to strip clubs. She's taken her adult sons to strip clubs. She's taken her students to strip clubs. She jokes that she has no shortage of voluntary research assistants.

She is the "Dr. Ruth" of lap dance.

Since 1995, Hanna has provided her expertise in scores of court cases. The first time, in Seattle, she said she had to crash through a picket line organized by a group calling itself "Washington Together Against Pornography."

Often, her cases boil down to strip club owners battling the Christian right, she says. "They want to get rid of these things, so that these things don't tempt them."

Sometimes she's called into garden-variety labor disputes between strippers and club owners. And once, she provided expert testimony in a murder trial.

More recently, Hanna was called in to defend Nite Moves, an adult juice bar near Albany, N.Y., against the state's tax man.

Imagine this scene: Grown men, enjoying healthy beverages and ballet performances on their laps, and all of a sudden the state tax auditor barges in and wants to collect $124,921.94 in sales tax, plus interest.

Nite Moves's accountants held that lap dances were like other artistic performances, and not subject to sales taxes. The club, armed with Hanna's expertise, took the auditor before a New York state administrative law judge and won. The auditor, however, appealed.

"The issue distills to whether the club's admission and private dance fees constitute charges for admission to a "live dramatic, choreographic or musical performance,'" the New York Supreme Court's Appellate Division in Albany wrote in its decision last week.

The court concluded that Nite Moves did not put up sufficient evidence to back its claims. It said that while Hanna viewed stage performances at the club, she did not actually observe the private performances there.

Their decision came down to a line as thin as a g-string.

"If you've gone to lots of baseball games, you can describe baseball," Hanna explained.

Andrew McCullough, the attorney for Nite Moves, hired Hanna for $250 an hour. He is based in Midvale, Utah. He attended Brigham Young University, yet defends adult entertainment venues against all sorts of onslaughts because it's the right thing to do, given the First Amendment and all.

"We're going to appeal," he said. "We hope eventually someone will listen to us. .. We'll browbeat them with evidence."

When you get right down to it, it's difficult to imagine a lap dance that isn't "live," "dramatic," "choreographic," "musical" and a "performance" as well. But New York state's taxing authorities seem to know better.

"The tax commission has now set themselves up as a dance critic," McCullough said.

Despite the appellate court's decision, a 31-page document Hanna provided for the court makes a compelling case for lap dances being little different than other live performances that aren't taxed:

"This individual patron-focused dance, a customized performance, takes place next to a patron's table or couch seat, and sometimes on the patron's lap," she wrote.

"The dancer artistically communicates to a patron, through her choreographed body movement, proximity, touch and dim light, the fantasy of "I am interested in you and you alone. I understand you. You're special and important to me. I want you. I desire you."

And then she walks away with the cash.

If this is not an art form, I don't know what is. I have never heard of a man going to his wife or girlfriend for a lap dance. This is something that is best performed by a talented professional who spends years perfecting the craft.

The problem with Nite Moves's case, judges concluded, was that it didn't provide sufficient evidence to back its claims. Do they need the club to bring in some performers and give them a lap dance?

"Maybe next time, that's exactly what we'll do," McCullough said.

(Al's Emporium, written by Dow Jones Newswires columnist Al Lewis, offers commentary and analysis on a wide range of business subjects through an unconventional perspective. Contact Al at al.lewis@dowjones.com or tellittoal.com)