Beyond that, proponents of Keynesian-style stimulus spending in the United States say that Japan’s approach failed to accomplish more not because of waste but because it was never tried wholeheartedly. They argue that instead of making one big push to pump up the economy with economic shock therapy, Japan spread its spending out over several years, diluting the effects.

After years of heavy spending in the first half of the 1990s, economists say, Japan’s leaders grew concerned about growing budget deficits and cut back too soon, snuffing out the recovery in its infancy, much as Roosevelt did to the American economy in 1936. Growth that, by 1996, had reached 3 percent was suffocated by premature spending cuts and tax increases, they say. While spending remained high in the late 1990s, Japan never gave the economy another full-fledged push, these economists say.

They also say that the size of Japan’s apparently successful stimulus in the early 1990s suggests that the United States will need to spend far more than the current $820 billion to get results. Between 1991 and 1995, Japan spent some $2.1 trillion on public works, in an economy roughly half as large as that of the United States, according to the Cabinet Office. “Stimulus worked in Japan when it was tried,” said David Weinstein, a professor of Japanese economics at Columbia University. “Japan’s lesson is that, if anything, the current U.S. stimulus will not be enough.”

Image Hamada was a beneficiary of public works spending. Credit... The New York Times

Most Japanese economists have tended to take a bleaker view of their nation’s track record, saying that Japan spent more than enough money, but wasted too much of it on roads to nowhere and other unneeded projects.

Dr. Ihori of the University of Tokyo did a survey of public works in the 1990s, concluding that the spending created almost no additional economic growth. Instead of spreading beneficial ripple effects across the economy, he found that the spending actually led to declines in business investment by driving out private investors. He also said job creation was too narrowly focused in the construction industry in rural areas to give much benefit to the overall economy.

He agreed with other critics that the 1990s stimulus failed because too much of it went to roads and bridges, overbuilding this already heavily developed nation. Critics also said decisions on how to spend the money were made behind closed doors by bureaucrats, politicians and the construction industry, and often reflected political considerations more than economic. Dr. Ihori said the United States appeared to be striking a better balance by investing in new energy and information-technology infrastructure as well as replacing aging infrastructure.