A year ago, the world stood on the brink. The collapse of the Lehman Brothers investment bank, the largest bankruptcy in American history, said more than enough about the weaknesses and excesses of the United States financial system to spark an escalating global crisis. Shares plummeted, banks came under pressure, and the world battened down for what, in most best-case scenarios, would be a deep recession.

Today, the clouds are already lifting and the imminent return of normal conditions is widely forecast. In historic terms, the recovery has been remarkably quick, thanks in large part to Governments' rapid enactment of huge stimulus and bail-out packages. Yet that good fortune carries its own dangers, not least that little has been learned and little has changed.

President Obama made this point on the first anniversary of Lehman's failure when he warned Wall St not to return to "reckless behaviour". Financial leaders were choosing to ignore the lessons, he said, adding that "normalcy cannot lead to complacency". The President's concerns are well-merited. If things have changed at all, they are in many respects for the worse. The White House declined to bail out Lehman Brothers, but, subsequently, starting with AIG, could see no option but to ride to the rescue of floundering once-mighty institutions. The consequences of their failure would be too severe. Quite simply, they were deemed too big to fail.

Twelve months on, they are even bigger. Bank mergers and acquisitions have consolidated lending power in even fewer hands. These institutions have good reason to believe that, because of their size, the Government will always bail them out. The same moral hazard applies to individuals, who were handed a similar message by Governments' decision to guarantee bank deposits and underpin finance companies.

One task now is to eradicate such expectations. It was right, therefore, for President Obama to remark that "those on Wall St cannot resume taking risks without regard for consequences, and expect the next time, American taxpayers will be there to break their fall". But his bark is much worse than his bite. More tellingly, the White House's plans for regulatory reform would not force those institutions to downsize or simplify their structures.

Indeed, the quick turnaround has dulled the prospects of meaningful reform that would provide safeguards and produce a more stable system. The White House wants tougher capital requirements for banks, a consumer protection agency to make rules for financial products, heightened oversight powers for the Federal Reserve, and conditions that would discourage companies from getting too big.

All are obvious responses, but face increasing opposition from those who claim they will undermine entrepreneurial risk-taking and limit success.

As conditions improve, the President's prospects of convincing Congress of their necessity diminish. Much the same applies to the plans of G20 Finance Ministers to cobble together a blueprint for changes to regulations, including capital levels for banks and global standards on pay.

The world showed a welcome unanimity and urgency in averting a meltdown. Now, there is the luxury of debate and potential divergence.

There will be other enduring impacts. Having spent so much to stimulate their economies, Governments are confronted by snowballing debt and interest. If the recovery, helped along also by lessons learned from the Great Depression, has been swift, the overhang will linger. Governments will have to grapple with the need to rein in public spending for a significant period, and investment expectations will remain subdued. If the world shows signs of mastering the immediate response to financial crises, the aftermath is proving far more problematic.