As several recent surveys make clear, concern about deficits and debt is rising sharply. An NBC/Wall Street Journal survey conducted in early May showed that the share of individuals rating “the deficit and government spending” as the top priority for the federal government to address has jumped since January from 13 to 20 percent—second only to job creation and economic growth. According to Gallup, “federal government debt” now ties with terrorism for the top spot in perceived threats to our future well-being. It is entirely possible that we are reaching an inflection point in public attitudes that will force the political system to change course.

Indeed, as Janet Hook shows in a well-reported piece in Monday’s Los Angeles Times, concerns about the deficit are already forcing congressional Democrats to scale back ambitious plans for continuing stimulus. Hook quotes Mark Mellman, a pollster who has long worked with Democrats, as saying that “there’s no question that people are almost as concerned about the deficit and government spending as about jobs. It is not just about the actual dollars—it is a metaphor for wasted money and lack of discipline and long-term economic decline.” A near-identical complex of concerns created an opening for a third-party presidential movement that garnered 19 percent of the vote in 1992 and strengthened the case for the policy of fiscal restraint Bill Clinton adopted in 1993.

All of this raises the question of whether public sentiment coincides with sound economics. A pretty good case can be made that it did in the 1990s, although it’s also possible to argue that the U.S. economy got a special boost during that decade from information technology and the winding-down of the Cold War. Today, many economists fear that we may be headed for a replay of Japan’s “lost decade” of slow growth, which in our case would condemn us to historically high levels of long-term unemployment.

That raises another question: What can the United States learn from the Japanese experience that should shape our own policy choices during this decade? This is more than an academic question, and the discussion cannot be confined to professional economists. After all, how to deal effectively with the twin challenges of economic growth and fiscal sustainability will be this decade’s dominant domestic policy debate.

It was in that context that I waded (some would say blundered) into a public colloquy with Paul Krugman and his legions of supporters. In the process, I discovered that Japan’s lost decade is surprisingly difficult to decode and that much of the data doesn’t mean what it appears to. Because Adam Posen of the Peterson Institute for International Economics seems to be the generally acknowledged guru of Japanese economics studies, I turned to a lecture he delivered at LSE last month. Posen argues that when the Japanese employed traditional Keynesian stimulus, it worked in the ways that conventional theory would predict and that the recovery faltered when the government unwisely pulled back from stimulative policies. (In that respect, Japanese policies in the late 1990s were akin to FDR’s turn toward restraint after 1936, which halted the recovery and renewed the decline.) Posen sums up as follows: