ARROYO GRANDE, Calif. (MarketWatch) -- First: Kiss the rally good-bye, says Jeremy Grantham, legendary CEO of the $101 billion GMO money-management firm.

Why? The market is overvalued 25%. A minimum 15% correction is coming in 2010, putting the Dow in the 8,000-9,000 range. The S&P 500? Not at 666 like last spring; maybe 800. Why a top? Black Friday? Dubai? Tiger Woods? All the dark films? The "2012" end of civilization? The post-apocalyptic "The Road?" Stop guessing, timing market turns is irrational.

Grantham's shift from bull to bear appears rational. Remember, earlier this year the Dow was near 6,000, banks near bankrupt, and we were praying for the new untested president to change America. In his latest editorial Grantham reminds us why his prediction made sense in the spring: "Regardless of the fundamentals, there would be a sharp rally. After a very large decline and a period of somewhat blind panic, it is simply the nature of the beast." Get it? A rally was predictable, based on the history of cycles.

Trust Grantham? 100%. Back in early 2007, he warned: "The First Truly Global Bubble: From Indian antiquities to modern Chinese art; from land in Panama to Mayfair; from forestry, infrastructure, and the junkiest bonds to mundane blue chips; it's bubble time. ... Everyone, everywhere is reinforcing one another. ... The bursting of the bubble will be across all countries and all assets ... no similar global event has occurred before."

Grantham was one of a small group of industry leaders who saw a crash coming as early as 2000. But political leaders were ideologically blind: Fed Czar Ben Bernanke said the collapsing markets were "contained." Our devious Treasury Czar Henry Paulson was misleading Fortune and all America: "This is far and away the strongest global economy I've seen in my business lifetime." Worse, former Fed Czar Alan Greenspan was busy writing his memoirs bragging about how he invented a "New World" out of Reaganomics, Ayn Rand's New Age wishful-thinking and an unregulated $670 trillion derivatives market.

Three clueless leaders.

Grantham bearish, short-term correction, long-term disaster

Now Grantham's warning us again: America's irrational nightmare will repeat. First, the short-term correction, 15% to 25%. But then long-term, a deadly warning: Disaster ahead. Why? Because America has "learned nothing," we are "condemning ourselves to another serious financial crisis in the not too-distant future."

Yes, Americans are predictably irrational, doomed to repeat history: Grantham points us to a key chart, his "favorite example of a last hurrah after the first leg of the 1929 crash." The similarity between 1929-30 and today are obvious: "After the sharp decline in the fall of 1929, the S&P 500 rallied 46% from its low in November to the rally high of April 12, 1930, then, of course, fell by over 80%."

Familiar? You bet. We've had our rally. Next, the plunge. Our irrationality plus history guarantees another ... only bigger.

A year ago America came dangerously close to the Great Depression 2. We "learned nothing." When psychologist Daniel Kahneman won the 2002 Nobel Prize in Economic Science for his work on irrationality in 2002, the sense was that behavioral economics would help Main Street become "less irrational," that behavioral sciences would make us all better investors, better consumers, better citizens.

Obama even made a big issue of working with behavioral scientists to minimize irrational behavior in America.

Obama gets failing grade in behavioral economics

But they turned against us. Behavioral scientists, behavioral economists and behavioral-finance experts have become the mortal enemies of Main Street America. Two ways: First, behaviorists consistently put us down by reminding us how irrational (stupid) we are. Second: They're using their minds, tools and technologies against us, helping Wall Street profile us as targets for investing products, bank customer fees, tax propaganda, etc.

They are paid mercenaries helping Wall Street scam Americans out of billions. They cannot be trusted, they have lost their independence and professional integrity. They are failing to expose the most toxic sources of irrationality: Wall Street, Congress, the White House.

And that's why when a guy like Jeremy Grantham comes along focusing us on the toxic irrationality at the top of America's leadership he deserves to be seen as one of America's best behavioral economists. He's one of the few honest behaviorists, exposing the irrationality of America's leaders.

So please listen closely to his 14-point analysis of the rampant irrationality at the highest level of American government today, because what he is also predicting is another catastrophic meltdown dead ahead.

1. Obama's shift into 'predictably irrational' economics

If Grantham ever was a fan, he's clearly disillusioned with the president. His 14 points expose the extremely irrational behavior of Obama breaking promises by turning Washington over to Wall Street, a blunder that will trigger the Great Depression 2. Grantham is cynical but subtle. If you want a more brutal attack, read Matt Taibbi's latest Rolling Stone feature: "Obama's Big Sellout," detailing how Obama, same as Bush, turned government over to Wall Street, to the same crooks who created the mess.

2. Bernanke's reappointment, a totally irrational blunder

"The most passionate cheerleader of Greenspan's follies ... completely clueless." A blunder "like reappointing the Titanic's captain" and "a wasted opportunity."

3. Summers, Geithner: Wall Street's newest Trojan Horses

Larry Summers blew "no warning whistles of impending doom back in 2006 and 2007." Earlier as Treasury Secretary he "beat back attempts to regulate" derivatives. Tim Geithner "sat in the very engine room of the USS Disaster and helped steer her onto the rocks" as New York Fed Czar. Still an irrational Obama appointed him, as Wall Street cheered.

4. Idiotic, irrational, greedy mortgage borrowers

"The more misguided or reckless the borrowers, the more determined the efforts to help them out," although "these efforts had limited effect." Short-term politics, bad economics.

5. Reckless, irrational and stupid home builders

They "magnificently overbuilt" for years." Still our irrational president stimulated "even more home building by giving new house buyers $8,000 each."

6. Nation of irrational overspenders and undersavers

Americans have been "dangerously overconsuming for the last 15 years." Still, our irrational politicians "encourage consumption and penalize savers by maintaining artificially low rates" fueling the same irrational speculation that created the meltdown.

7. America's too-Irrational-to-fail' banking system

Our banking "system shows every sign of being out of control." Make it simpler, smaller, "so they can be allowed to fail." Separate the "dangerously risk-seeking hedge fund heart from the banking system." Instead Obama set up a bizarre, irrational policy ... force them to be bigger." Now they're "at extreme tilt to risk-taking: it's practically a cliff!"

8. Wall Street's unconscionable crooked mega-bonuses

"Two-thirds of Goldman's huge profits went for bonuses ... largest ever." Last year the "same guys were on the edge of a run on the bank ... saved only by government." Our irrational president upset "the formerly infallible workings of capitalism."

9. Corporate America's grossly overpaid CEOs

"Galling," says Grantham: When he came to America in 1964 "the ratio of CEO pay to the average worker was ... between 20/1 and 40/1." That had "held for the previous 30 years. By 2006, this ratio had exploded to between 400/1 and 600/1 ... obscene."

10. Our irrationally overleveraged, zombie companies

Wall Street has "so overstimulated the risk-taking environment that junky, weak, marginal companies and zombie banks" outperform, with "junk over the great blue chips." We let losers "live to compete against the companies that actually deserve to be survivors." That's "not healthy for the long-term well-being of the economy."

11. Our irrationally managed U.S. auto industry

"Most short-sighted industry of the last 20 (40?) years, and one of the worst managed."

12. A nation addicted to automobiles, dying for more oil

"We chew up a dangerously large amount of Middle Eastern oil ... ruinous for our global political well-being (and ability to avoid war)" and bad for "an overheating world." Still, our irrational politicians are subsidizing more car purchases.

13. Stock options give CEOs a legal right to steal from shareholders

They're robbing us: Corporate CEOs have a "legalized way to abscond with the stockholders' equity." If management messes up and the stock crashes, they just "rewrite the options at new low prices ... no serious attempt to match stock option ... to the building of long-term franchise value. Instead, the motto is: grab it now and run!"

14. Finally, Grantham's irrational 'old nemesis, Greenspan'

He gets "the title of Maestro in the U.S. and is knighted by the Queen ... for thoroughly demolishing the integrity of the U.S. financial system. He overtly ignored the great threat of bubbles in asset classes and, in fact, encouraged them. He Ayn Rand-ishly facilitated the progressive dismantling of governmental restrictions on financial behavior, he deliberately kept real interest rates at zero for years, etc., etc., etc. You have heard it before. ... In the good old days, he would have been set in the village stocks, and not the kind you buy and sell. And I would have been right there, Alan, with very ripe tomatoes."

In the end Grantham encourages everyone to read a John Kay article in the Financial Times. Kay's title says it all: "Our banks are beyond the control of mere mortals." He advises investors to "follow an aphorism of Warren Buffett's: 'Invest only in businesses that an idiot can run, because sooner or later an idiot will.'"

Rereading Buffett's wisdom I wonder: Perhaps America really is a "business" that nobody can run? Not the best and brightest. Nor an idiot. And certainly not our too-clever behavioral scientists.

Moreover, "people" are not the problem. The 1982 classic "In Search of Excellence" tells us that 85% of organizational failures were systemic, not people caused. "It's the system stupid." That means America, our economy, our markets, our capitalist system have become too big, too complex, too out-of-control, too unmanageable.

Our wealthy elite already know that and are grabbing what's left. The "idiot" masses could regain control, but only in a 1776-style revolution, except they're too docile, too irrational to revolt.