If you think Gordon Brown has a huge political problem with the imminent nationalisation of Northern Rock - which, of course, he has, largely because of his own procrastination in taking this inevitable decision - have a look across the Atlantic at what has happened this week to Citigroup and Merrill Lynch, respectively the world's biggest bank and the world's biggest stockbroking firm (at least until their recent troubles).

On Tuesday these two companies, universally recognised as the biggest and brashest symbols of America's financial hegemony and the triumph of market capitalism in every corner of the world, were forced to raise $21billion of new capital from national investment funds owned by governments in Asia and Middle East. These bailouts raised to $35billion the rescue capital received by Merrill Lynch and Citigroup in the past three months and to almost $100billion the total cash injections into Western financial institutions from the sovereign wealth funds or ruling families of Abu Dhabi, Kuwait, Dubai, Saudi Arabia, China, Singapore and South Korea.

Everybody can see the irony in the proudest and loudest proponents of American-style private enterprise limping, cap in hand, around the capitals of Asia and Arabia, begging for some government assistance, after the private money managers on Wall Street have kicked them in the teeth. But, beyond dramatic irony, the truly remarkable feature of this week's financial news was not the size or origin of the new investments, which were pretty much as expected, but the market reaction to this news.

Instead of heaving a sigh of relief that the two largest and most troubled institutions at the heart of last year's credit crunch had replaced their managements and raised enough capital to survive and get back to business, investors and analysts redoubled their panic.

This deeply pessimistic market reaction, unless it is reversed in the next few days (which, of course, it still may be) raises two much bigger issues beyond the obvious Schadenfreude, which we all feel when the rich and arrogant are brought low. The negative reaction implies, first, that these banks and other US banks will have to raise even more money in the near future from Asia and the Middle East - and similar recapitalisations will almost certainly be needed in Europe as well in the next month or two.

As a result, Asian and energy-producing sovereign wealth funds will soon become the biggest shareholders in most of the leading American and European financial institutions. In this sense, the bailouts of Citigroup and Merrill Lynch will be remembered as milestones, marking a decisive shift in the centre of gravity of the world economy towards Asia after five centuries of financial, economic and therefore political dominance by Europe and America.

Secondly, if the markets prove right in their initial pessimistic reaction, then these cash injections will inevitably be seen not as canny investments but as government bailouts. That, in turn, will imply the present global financial crisis simply cannot be solved by private market forces. If market confidence cannot be restored in stricken banks, however much new money they raise and whatever management changes they undertake, then governments and regulators around the world will be faced with a stark choice.

Either they will have to accept a long period of financial paralysis, leading inevitably to a deep global recession and maybe even a Japanese-style decade of depression or they will have to step in with a Plan B, involving public sector intervention of some kind that overrules the judgment of market forces. This, too, would represent an important milestone in what looked until recently like the inevitable progress of free-market capitalism around the world.

The first of these two momentous events - the shift in the world's economic centre of gravity - raises all sorts of questions about the political and social, as well as economic, philosophies that will dominate world history in the generations ahead. But these are question for years or decades of calm reflection, not for instant judgments in the heat of a financial crisis.

The second issue - whether government intervention will be required - will now have to be faced very quickly, probably within a few weeks. Whether this intervention involves government guarantees and subsidies or drastic reductions in interest rates or enforced changes in lending and mortgage contracts or other regulatory and accounting reforms, governments around the world will surely be willing to act on a larger scale than anyone would have imagined a few months ago.

But before governments throw caution to the winds - whether as regulators or as central bankers or as investors in financial institutions - another question needs to be raised and urgently answered. What quid pro quo should be demanded from the banks and financial institutions that receive public support?

Industrialists often ask why bankers should get government support that is not available to other businesses that run into trouble. But the answer is quite simple: banking is different from other industries because depositors' savings must be protected and, even more importantly, because a breakdown in bank lending has catastrophic and universal effects on the economy as a whole. This simple reality makes it inevitable that governments will come to the bankers' rescue but it should also impose duties and responsibilities on the banks. The lesson of the present crisis is that these duties of care have been ignored by many bankers - and still continue to be flouted.

Today, even as they hovver on the brink of insolvency and are forced to raise billions of dollars of new money to survive, most of the leading international banks are paying out large - and in some cases increasing - bonuses to their employees, enormous golden parachutes to their failed directors and dividends to their shareholders.

In the case of Morgan Stanley, for example, the $5billion of new funding raised from the Chinese Government has been almost exactly matched by an increase in the bonus pool for payment to its supposedly talented employees. Citi, meanwhile, after paying out more than $100million to its sacked chief executive, is now planning to pay out roughly half the new capital it raised this week as a dividend next month.

If banks are to continue receiving implicit government guarantees then regulatory steps will have to be taken to ensure that these guarantees are reflected in their financial management, remuneration policies and risk controls. How exactly this can be done is a complex subject which economists, financiers and politicians will need to debate and to which different countries will probably find different answers.

But something clearly must be done to ensure that banks, their employees and their shareholders pay an adequate price for the implicit insurance they enjoy from governments and taxpayers - whether those governments are in America and Europe or in Asia and the Middle East. In the case of Britain, ensuring that the shareholders of Northern Rock lose every penny of their investment would be a good place to start.

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