Constant readers may recall that several weeks ago I suggested we were approaching an opportune time to purchase a new car. The reasoning went this way: Sales are slumping, especially among the so-called exotic brands; selection is such that desperate dealers are offering a cornucopia of splendid automobiles at fire-sale prices; demand is down, supply is up; and one doesn't have to reread The Wealth of Nations to understand why favorable deals await diligent buyers. And that was before it became apparent that Black Monday might extend into the next two years.

Although the stock market has since wobbled back off the mat, the doomsayers are out in force, telling us that a depression is imminent. Therefore, what could once be labeled an opportunity has now become a national duty: Every red-blooded American must step up and buy a car.

Buy a new car, you say? Am I crazy? Haven't I been reading about how we're going to be living in caves and that the next nouvelle cuisine will be based on lichens, grubs and small animals? Don't I know that Donald Trump's newest venture will be a split-level debtor's prison in Southampton? This is it, you say: The fat lady sang and then she bailed out for the bread lines. This is so serious that even Congress is cutting back. How in the name of John Kenneth Galbraith can one consider buying a car?

Wait a minute. I am not suggesting going out and buying any old ordinary car, especially a reasonably priced car -- no wimping out with a Hyundai or bargaining for an Escort. No middle ground here, no hanging back -- you've got to go for the big-bucks cars. This is about saving the economy.

You do want a consumer-based society, don't you? Well, then, shake loose the old wallet and do your part. Spending is the engine of progress: It's a simple economic fact. I mean, do the Amish spend? Do they drive around in BMWs or horse-drawn carts? Look where austerity has gotten them. Oh sure, on the surface they seem happy and rosy-cheeked, but I'll bet the bozos in Detroit are convinced that, deep inside their starched hearts, even the Amish crave six-speaker stereos, cruise control and 16-valve performance.

You want to live in the 20th century? Then go out and buy a car. Too much of the simple life and pretty soon it's back to the 19th century, when dunking for apples and square dancing were considered lots of fun. You say you don't have any money? Your entire grubstake in Amalgamated Consolidated went poof like a Fourth of July salute? So what? America is built on debt.

Debt is the currency of the land. The showrooms are loaded with cars. Semi- suicidal car salesmen, bound to life only by their ground-floor locations, are ready to deal. Nothing stands between you and the soapy-soft leather of a really expensive car but a few simple monthly installments and a balloon payment down the road (about the time you trade the thing in on a Lamborghini or an Aston- Martin Lagonda). Those guys in Ultrasuede are sitting on their own debt in the form of bank loans and floor plans, and they're plenty eager to transfer it to you.

Here's how you go about taking advantage of this situation. Say you want a Mercedes-Benz 560 SEL, but the $70,000 price tag is a little out of your league -- perhaps by about 69 grand. No problem. (Yes, it would be better to buy a Cadillac Allante or something else American, but you shouldn't let chauvinism get out of hand.) First, get some clothes. It's hard to do serious business in a Mercedes-Benz dealership when you're wearing a lime-green double-knit leisure suit and Corfam dress shoes. This requires something in tweed and gray worsted. Yes, slacks and a tailored sport coat with a button-down oxford cloth shirt and loafers, preferably with tassels. Practice talking with your lower jaw locked. Learn to say "I'm interested in a 560 SEL" without moving your teeth. Finally, a one-day rental of a Cadillac Coupe de Ville from Avis will provide sufficiently upscale transportation to the point of purchase. From there, your Mercedes-Benz (or BMW or Jaguar or Porsche) is a mere key toss away.

In today's crazed environment, you will be greeted like the Aga Khan by his seething throng. Nothing will be too good for you, the first potential customer to brighten the threshold in days. All it will boil down to is choice of color. Believe me, there will be plenty of everything, including puce and chrome yellow. A few quick signatures, a couple of handshakes, and you'll be out the door. With a little luck, your new set of wheels will boost you so high up the socioeconomic ladder that you may actually be able to make a payment or two.

Do not -- I repeat, do not -- flag at the last minute and permit pangs of conscience to hinder your quest. Remember that buying things with money you don't have is as American as eating in fast-food joints and putting spinner hubcaps on your Buick. The government does it every day, so who's to say a little of the same by the citizenry is wrong? Besides, the life you save may be your car dealer's. ::