jamessaft1.jpg (James Saft is a Reuters columnist. The opinions expressed are his own)

Don’t expect the year-long rally in risky assets to be undermined any time soon by the Federal Reserve becoming concerned about inflation.

The old metaphor — that the Fed’s job is to take away the punchbowl just when the party starts getting good — just doesn’t apply in the current circumstances. That’s not to say inflation isn’t a threat in the medium term — it is virtually a promise.

But punchbowl thinking dates from a time when firstly the Fed was presumed to have a degree of control over events we now know is not true and secondly to an era when asset prices were the caboose rather than the engine of the economic train.

Even with an economy that is now growing, the risk of a self-reinforcing de-leveraging spiral is enough to ensure that the Fed will not pull the trigger on tightening any time soon.

“Asset prices are embedded not only in our psyche, but the actual growth rate of our economy. If they don’t go up, economies don’t do well, and when they go down, the economy can be horrid,” Pimco bond chief Bill Gross writes in his most recent letter to investors.

Gross argues that leverage inflated the price of assets even as investment in the U.S. real economy flagged. As this happened the U.S. economy became ever more dependent on asset prices and on the sectors, such as finance, which intermediated the borrowing. When the debt and asset bubble is pinched, the whole edifice is threatened, leading to a response like the one we’ve seen: massive and overwhelming aid trained on markets irrespective of the costs.