Such "structural shifts are incredibly hard to predict," agreed Gus Faucher, the director of macroeconomics at Moody's Economy.com.

Really?

Take the nation's largest existing government medicine scheme, Medicare -- please. "The two primary lessons of Medicare," wrote Steven Hayward and Erik Peterson in "The Medicare Monster, A Cautionary Tale" (Reason magazine, January 1993 -- www.reason.com/news/show/29339.html) "are the chronic problem of woefully underestimating program costs and the impossibility of genuine cost control. ...

"At its start, in 1966, Medicare cost $3 billion. The House Ways and Means Committee estimated that Medicare would cost only about $12 billion by 1990 (a figure that included an allowance for inflation). This was a supposedly 'conservative' estimate. But in 1990 Medicare actually cost $107 billion."

That means Medicare managed to cost nine times the original projection, only 27 years after it started. Benefit outlays as of 2007? Thirty-two times initial estimates.

As for the new Democratic health care proposals, the Congressional Budget Office put the 10-year price at between $1 trillion and $1.6 trillion, depending on the plan.

The Obama administration and lawmakers further promise that any health plan would be "paid for," meaning that it wouldn't increase the federal deficit. Obama and top Democrats say they can fund their plans with a combination of health care cost savings and as-yet-unspecified higher taxes.

How much in new taxes?

Taking those figures of $1 trillion and $1.6 trillion, and multiplying by either nine (if we want a realistic estimate of costs, 27 years out) or by 32 (if we want some sense of what Obama-KennedyCare might cost by 2054) um ... would that start to add up to what Sen. Everett Dirksen used to call "real money"?

And that's assuming everyone is being "straight." The Bush administration was widely criticized after revelations it deliberately underestimated the cost of its new Medicare prescription-drug initiative as Congress considered the plan in 2003. Some Republicans had vowed not to back any bill with a price tag of more than $400 billion over 10 years, so the administration said publicly it would cost less than that. Later, Medicare officials conceded that they hid their internal estimate of $551 billion.

The only thing we know for sure is that when competitors have an incentive to lower costs while adding features in order to gain more market share, costs on all kinds of things tend to drop. Compare prices -- in inflation-adjusted dollars -- for home computers and color televisions to what such things cost when first introduced.

On the other hand, when a product or service is delivered by a government monopoly, the opposite happens. Job security comes first, and quality tends to drop, even as prices go through the roof.