Will the rescuers arrive in the nick of time? Not necessarily. This movie may not be ''55 Days at Peking'' after all. It may be ''A Bridge Too Far.''

A few months ago the vast majority of business economists mocked concerns about a ''double dip,'' a second leg to the downturn. But there were a few dogged iconoclasts out there, most notably Stephen Roach at Morgan Stanley. As I've repeatedly said in this column, the arguments of the double-dippers made a lot of sense. And their story now looks more plausible than ever.

The basic point is that the recession of 2001 wasn't a typical postwar slump, brought on when an inflation-fighting Fed raises interest rates and easily ended by a snapback in housing and consumer spending when the Fed brings rates back down again. This was a prewar-style recession, a morning after brought on by irrational exuberance. To fight this recession the Fed needs more than a snapback; it needs soaring household spending to offset moribund business investment. And to do that, as Paul McCulley of Pimco put it, Alan Greenspan needs to create a housing bubble to replace the Nasdaq bubble.

Judging by Mr. Greenspan's remarkably cheerful recent testimony, he still thinks he can pull that off. But the Fed chairman's crystal ball has been cloudy lately; remember how he urged Congress to cut taxes to head off the risk of excessive budget surpluses? And a sober look at recent data is not encouraging.

On the surface, the sharp drop in the economy's growth, from 5 percent in the first quarter to 1 percent in the second, is disheartening. Under the surface, it's quite a lot worse. Even in the first quarter, investment and consumer spending were sluggish; most of the growth came as businesses stopped running down their inventories. In the second quarter, inventories were the whole story: final demand actually fell. And lately straws in the wind that often give advance warning of changes in official statistics, like mall traffic, have been blowing the wrong way.