There is a very simple reason why US Treasury Secretary Henry Paulson's (inset) $700bn bail-out package was such a tough sell to politicians and the American people – it won't really work.

Despite the historically massive expenditure and all the little clauses to make sure Wall Street fat cats get there comeuppance, the plan is unlikely to do anything to save the biggest economy in the world from a long and crippling downturn.

It will doubtless save some banks from collapse, but is that really worth the government putting itself on the hook for nearly a trillion dollars?

But, that's not the half of it.

Not bailing out Wall Street with as much money as it would take to launch an American National Health Service presented an even bleaker prospect – a financial nuclear winter that could last a generation.

In short, we're doomed if we do and doomed if we don't get Paulson's billions – perhaps the greatest economic dichotomy America has ever faced.

You can always rely on "Neutron" Jack Welch, the former GE boss and all-round tough talker, to tell it how it is. "I now believe we are in for one hell of a deep downturn," Welch told the World Business Forum in New York last Wednesday, adding that the first quarter of 2009 will be "brutal".

Until recently, Welch said, he had believed the US economy could avoid recession, but he has changed his mind, despite the bail-out. "I am now caving," he said. "Get ready for real tough times. They're coming."

And Welch is not alone in his gloomy outlook. A day after the New York meeting, Peer Steinbruck, the German finance minister, predicted that America will soon be knocked off its perch as the world's leading economic superpower.

Peel away this hyperbole, however, and consider the ramifications of such large-scale government intervention into the free market as Paulson's bail-out represents and even Steinbruck's seemingly gratuitous slight sounds plausible.

The first question anyone wondering if the bail-out will work should ask should surely be whether or not $700bn is enough, or indeed too much, to fix things. And where did that figure come from anyway?

Assuming the plan actually gets off the ground and the Treasury is able to organise some kind of workable asset sale, what will happen to the US economy once the banks have been "saved"?

Will house prices automatically start to stabilise? Will jobs be created as if by magic? Will Americans suddenly find they have disposable income on hand to get their consumer-weighted economy whirring away again? Of course not. And that is the plan's biggest fault.

In fact it is entirely possible that the US economy will become even more paralysed after the bail-out than it is today because the government will put such a strain on already creaking public finances that it will not be in a position to provide any sort of stimulus for a long time to come.

Most critics of the Paulson plan express concern about the American tax payer shelling out billions of dollars to bail out greedy Wall Street bankers.

But this is a misconception. The taxpayer is not paying for this, nor will they ever, because America doesn't have $700bn of taxpayer's money. The Federal government is in debt to the tune of $9.8 trillion.

The entire sum will likely be borrowed from foreign governments and other purchasers of US Treasury bonds, which creates further problems.

Such a huge increase in borrowing will drive the already weakened dollar down further still, which will not only suck more life blood out of the American economy but drive up the dollar-denominated price of oil and other commodities adding inflationary pressure into the bargain.

What is more, the bail-out will cripple whoever wins the next election. Obama can forget about spending increases and McCain won't have any room for tax cuts. The next president will also face the prospect of a global depression to manage, and with it the possibility of strained relations with foreign governments.

After the Latin American financial crisis in the 1980s, the leading countries of Asia and the Pacific Rim said such a collapse could never happen to them. But in just a few short years their economies were falling like dominoes.

And as Japan, Singapore and Taiwan were failing Americans looked on and said that such endemic economic troubles only happen in developing economies like those in Asia and Latin America so they could never happen to their great nation.

But guess what? They were all wrong.

The only questions that remain are how long America will remain in crisis and can it claw its way out with its dominant position intact?