TV's Boss From Hell -- `Thirtysomething's' Iceman/Adman Is Portrayed By An Actor Who Gets Passionate About His Own Issues

LOS ANGELES - Brace yourself. You are about to glimpse the Miles Drentell that might have been.

``I shouldn't show you this,'' confesses David Clennon, the veteran actor who plays Miles, the advertising mogul whose personality chills like liquid nitrogen on the TV series ``thirtysomething.'' Clennon pops a videotape into his clunky VCR, a relic possessing the size and heft of a small anvil.

The tape is a first cut of the episode where Miles made his first appearance, during the Emmy-winning show's second season.

Miles flickers to life. He stands in his office at DAA, the large and prosperous Philadelphia ad agency of which he is president, autocrat, puppetmaster. He greets Michael Steadman and Elliot Weston, the ``thirtysomething'' best friends and partners in their own ad agency, which is about to go belly up. They have come to ask for help.

Miles cuts them off at the knees. But he does it boisterously. He wears a cardigan sweater, gestures expansively and - get this - pops handfuls of trail mix into his mouth.

``My idea,'' says Clennon, hitting the STOP button and shaking his head.

Oh, the goose bumps that might never have been raised by this character, light years away from the Miles we have come to love to loathe, if this version hadn't wound up on the cutting-room floor.

``It was somewhere in the reshooting of that scene that Miles gelled,'' says Clennon. ``Marshall (Herskovitz, who with Ed Zwick co-created ``thirtysomething'' and Clennon's character) said play it much more powerful and remote. Above them. A man who doesn't have to prove anything to them.''

The Miles who emerged in the final cut of that episode and has been fleshed out during the past season and a half seems so remote you'd need a Sherpa guide to reach him. He does nothing expansively. He even seems to breathe without moving his rib cage.

Trail mix? Try sushi. Sweaters in the office? Ummmmm, no. Miles is a stiletto in a $1,000 double-breasted Armani sheath.

He is every employee's worst nightmare. Maybe that is why he has captured the imagination of so many wage slaves.

Remember the nature movies you saw in junior-high biology class, where a mouse is dropped into an aquarium containing a rattlesnake to show how venom affects the mouse's central nervous system?

``I'm sure Miles shows them as motivational films,'' says Joseph Dougherty, a ``thirtysomething'' writer who, along with Ann Hamilton, has written most of the episodes where Miles figures prominently.

``Anybody who's in any office structure above a 7-Eleven, they see parts of their boss in Miles,'' says Dougherty. ``We get calls.''

David Clennon gets a call. It is one of his agents. Something about a part in Steven Bochco's new cops-and-choirs show on ABC, ``Cop Rock.''

Cordless phone in hand, Clennon drifts through his Santa Monica condominium, a modest place so far from the beach that the only whoosh comes from the traffic, not the surf. One bookcase is filled with neat stacks of magazines. Most, except for the alumni monthly from Clennon's alma mater, Notre Dame, are political, liberal: The Nation, Mother Jones, The Progressive.

Clennon is still dressed in the oxblood Bally shoes and navy blue suit pants that he wore this morning to a press conference publicizing a TV spot paid for by a coalition of groups seeking a cut in U.S. military aid to El Salvador, a spot many TV stations have refused to air. Clennon narrated the commercial, which shows a check being written to the IRS while being stained by drops of blood.

Politics is Clennon's passion - he has been involved with the El Salvador cause for 10 years, for example; the clothing is almost a disguise. Before landing the role of Miles Drentell, he owned one suit. Vintage 1981, it came from wardrobe during ``Missing,'' the Costa Gavras film in which Clennon played a bureaucrat.

``I hate to shop for clothes,'' he explains after finishing his phone call. Accordingly, he pressed his agents to negotiate for him to keep the suits from ``thirtysomething,'' in which Miles was slated to appear in only three episodes.

As it has turned out, the part has been a boon to more than his wardrobe.

Clennon had appeared in an early TV movie by Herskovitz and Zwick called ``Special Bulletin,'' and was performing in regional theater in L.A. when he was cast as Miles.

``I used to think the quality of episodic TV was so poor it was really a waste of time to do it, let alone watch it,'' Clennon says. ``But it had been a bad year, so I was ready to do just about anything.''

Until then, he paid the rent during his career with supporting roles in more than a dozen feature films, many of them critically acclaimed - ``Coming Home,'' ``Being There,'' ``Missing,'' ``The Right Stuff,'' ``Star 80.'' Often, he played what you might call white-collar weasels.

``Here's just another white-collar creep,'' Clennon recalls thinking when he read the part of Miles.

He was wrong. Miles is the creepiest white-collar creep ever.

``Miles Drentell could have easily done a few scenes and disappeared forever. But he made such a strong impact that we felt we could get a lot of mileage out of Michael and Elliott going to work for him,'' says Scott Winant, the ``thirtysomething'' supervising producer who won an Emmy for directing last season's two-part finale, where Miles thwarted a hostile takeover of DAA orchestrated from the inside by Michael and Elliott.

In tonight's episode (10 p.m., Channel 4) Miles decides to cut his agency's expenses and makes Michael his hatchet man. It is classic Miles, the way he maneuvers with both ruthlessness and obliquity.

Sometime during last season, Miles seemed to turn into a topic of Wednesday-morning water-cooler confabs and E-mail speculation. There is much room to speculate.

Unlike the regular cast of ``thirtysomething'' characters, we seldom see Miles outside his lair at DAA. This changed dramatically several weeks ago in the episode where he dated, and eventually made a bungled pass at, Michael's cousin Melissa.

Too, the other characters tend to run off at the mouth. Miles, on the other hand, selects words like some men select ties. Slowly. With great thought. When he finally speaks, it is usually cryptically, often in parables, some of which he draws from Japanese samurai management texts.

``When you write Miles,'' says Dougherty, ``what you do is figure out exactly what he means, and then tap dance around it for about a page and a half.''

Believe this: Miles himself never would have showed us the videotape of proto-Miles. Miles is a concealer, not a revealer. He knows that knowledge is a weapon, and that the odds are best when the enemy is defenseless.

While talking about last season's finale, Winant says something that could easily be applied to almost every situation in which Miles has appeared: ``Miles knows everything,'' Winant says, ``and reveals nothing.''

Here is some of what David Clennon reveals about himself, and what he knows about Miles:

Clennon was born 47 years ago and grew up in Waukegan, Ill., the son of an accountant.

As a child he wanted to be a farmer. He went to Notre Dame to become an astronaut instead, but was deterred by physics. A college roommate persuaded him in his sophomore year to try out for ``Hamlet,'' in which he played the part of Guildenstern. It was the first of many parts.

Miles attended Princeton.

Clennon can't recall exactly what attracted him to the stage, but offers that it may have seemed a good way to meet girls.

He has met girls, but not married any; Miles is divorced.

After earning his B.A. in English lit, Clennon studied drama at Yale. He resisted the Vietnam draft. On the verge of induction, the Army diagnosed him as too depressive to serve.

Miles served in Vietnam, as part of the ``hearts and minds'' propaganda campaign.

Clennon, at 6-foot-2, thinks his posture is poor and continually reminds himself, when playing Miles, to stand erect. He imagines his mother telling him, as a child, to stop slouching.

Miles drives a Porsche.

Clennon drives a Geo Prizm, an econobox that meets his three criteria: It gets good gas mileage; it received a Consumer Reports recommendation; it was built under a United Auto Workers contract.

Clennon recreates by running at a local junior-high track and swimming at a nearby YMCA.

Miles relaxes by hunting quail.

Clennon has a fantasy of controlling life's situations the way Miles does. ``I would like to pretend that I don't have those wishes, but I do,'' he says. ``I think in some way they get fulfilled when I enact this character. So I can say I'm a Democrat or a collectivist or egalitarian in real life, but I get off portraying this manipulative, selfish, successful character.''

Clennon has trouble deciding on a favorite line of Miles dialogue. But Joseph Dougherty, who writes many of them, does not. It was uttered when Michael asked Miles a simple question: How was he feeling?

``Glutinous with self-approbation,'' Miles answered.

Dougherty admits to borrowing the line from the Hitchcock movie ``Frenzy,'' but it fit Miles like a handmade shirt. It also wound up on the back of T-shirts specially made for the ``thirtysomething'' crew, with Clennon's face glowers from the cotton.

``I work for Miles Drentell,'' the shirts say. We probably all do, or have, or will.