When has it failed? Keynes has not really been followed since Reagan. It is the neoclassists and the neoconservatives that are failing now.

I'm beginning to think that Keynesian economics is a lot like communism: "It's never worked because no one was doing it right."

Maybe it just can't be done right. Maybe the problem is people.

Oh, but it did work. It worked when it was actually practiced from the late 40s to the 70s when the US experiences the highest rates of economic growth in its history. During the 70s the US had about the highest average income levels in its history too (this was briefly matched during the Clinton administration but then incomes fell again).

No, it failed to cure the depression - World War II cured the depression. It was not practiced from the 40's to the 70's. The average family paid 4% in federal taxes in 1950. JFK cut taxes in the early 60's which caused a spurt of economic growth. Reagan cut tax rates (revenues actually INCREASED) in the 80's which again caused a period of growth. We have still not paid the price for FDR (Social Security) and Lyndon Johnson's (Medicare) programs because we have been borrowing money for 30 years. I guess you must think that trillions of dollars of debt is a sign of a good economy.

Do you mean that his theories caused this downturn, or that the government stimulus is a mistaken way to recover from it? Or both?

Sounds about right (both). Causes of this downturn: --Low interest rates/easy money during the Greenspan years (central planning) --The housing crisis precipitated by government interventions such as Fannie, Freddie, anti-redlining regulations, etc. encouraging/forcing banks to lend to those who would be unable to repay.

The future has yet to pan out but I, for one, expect the pork ("stimulus") to offer some short-term boosts/bubbles as people make cash grabs. But in the long term as people realize that the green paper is being devalued and they are encouraged to make poor investments things will get markedly worse or at best we'll miss out on what could have been. E.g., people are building windmills and ethanol stills instead of coal plants and oil rigs because the former are subsidized and the latter increasingly regulated. Unfortunately, it's a gamble as to whether windmills will match the effort put into them and there's a growing consensus that ethanol costs more than it affords outright.

Think of it this way: If you put a dollar into a decent investment, you might expect a $1.10 in return. Similarly if you made a bad investment you might get $0.95 back. Now expand that to the net worth of the whole country. Depending on how well we manage our existing wealth in spite of the disincentives, it could take a long time to burn through 60 trillion dollars a nickel at a time. Maybe we'll continue to grow but the opportunity costs will mean it happens by pennies instead of by nickels.