Amid increasingly turbulent credit markets and ever-weaker reports on the economy, the Federal Reserve has been unusually swift and determined in its lowering of the overnight lending rate.

The White House and Congress have moved quickly as well, approving rebates for families and tax breaks for businesses. And more monetary easing from the Fed could well be on the way.

The central question for the economy is this: Will this medicine work? The same question was asked repeatedly in Japan during its "lost decade" of the 1990s. Unfortunately, as was the case in Japan, the answer may be no.

If the economy of the United States was entering a standard cyclical downturn, there would be good reason to believe that a timely counter-cyclical stimulus like that devised by Washington would be effective. But this is not a standard cyclical downturn. It is a post-bubble recession.

The US is now going through its second post-bubble downturn in seven years. Yet this one stands in sharp contrast to the post-bubble shakeout in the stock market during 2000 and 2001. Back then, there was a collapse in business capital spending, a sector that peaked at only 13 percent of real gross domestic product.

The current recession has been set off by the simultaneous bursting of property and credit bubbles. The unwinding of these excesses is likely to exact a lasting toll on both homebuilders and American consumers. Those two economic sectors collectively peaked at 78 percent of gross domestic product, or fully six times the share of the sector that pushed the country into recession seven years ago.