Now, some minds are changing. The process of labor market adjustment is “gummier than anybody realized,” said Mr. Hanson, a professor at the University of California at San Diego. The persistent negative effects of Chinese trade on much of the American labor market have “toppled much of the received wisdom about the impact of trade on labor markets,” Mr. Hanson wrote with his co-authors, especially the “consensus that trade could be strongly redistributive in theory but was relatively benign in practice.”

In fairness to the economics profession, that consensus emerged mostly because workers actually did adjust more easily to trade in the past. Global trade soared in the four decades after World War II without apparent negative effects on labor markets in rich countries. But most of this trade was between rich countries, and exposing Ohio workers to competition with Ontario workers wasn’t that much different from the competition they always had with Michigan workers.

As Mr. Gordon and his co-authors describe, the rise of trade with China since 1991 increasingly exposed American workers to competition from those who would work for much less, causing particular problems for lower-skilled workers.

There is also a damaging trade imbalance. The rise of Chinese exports would not have had such negative effects on the American labor market if it had been offset by a commensurate rise of Chinese imports. More exports to China would have created American jobs, both in exporting industries and in the sectors that support those industries, making it easier for displaced workers to find new jobs.

Instead, China has run a persistent trade surplus. What that really means is that Chinese consumers save much of their income from export industries instead of using it to consume imports. This is one of the major “global imbalances” identified by Ben Bernanke, the former Fed chief, as a driver of both high unemployment and asset price bubbles in the United States.