A report from the Congressional Research Service reaches the same conclusion and adds South Korea and Taiwan to the list of countries with declining factory jobs.
Manufacturing's story parallels agriculture's. Improved seeds, mechanization, planting and harvesting techniques enable fewer people to produce more food. Greater productivity lowers relative prices.
But for food and manufactured goods, lower prices do not stimulate a corresponding rise in demand. How many refrigerators, after all, do consumers want?
Again, in economics lingo, demand for manufactured goods is "price inelastic," say the two economists. A 10 percent fall in prices does not increase demand 10 percent.)
Lower prices for manufactured products frees up money to spend on services - health care, education, travel, apps.
By this process, living standards rise. Gains from manufacturing trade, through lower prices and greater choice, do the same. Lawrence and Edwards estimate these at about $1,000 for each American; about half reflect trade with emerging-market nations.
The lesson is that trade's virtues tend to be underrated and its vices overstated.
Although imports worsen the secular loss of manufacturing jobs, the perceived impact is probably greater than the actual impact.
Suppose, say the two economists, the United States had no manufacturing trade deficit. This would, they estimate, boost U.S. factory jobs by 2.7 million.
That's a lot of jobs and would significantly add to manufacturing's total, now about 12 million. Still, it pales beside the Great Recession's employment loss (8.7 million) or total payroll employment (about 135 million).
Even if these factory jobs magically materialized, gains might be temporary. Advancing productivity could soon erode the total.
Similarly, it's true that foreign competition puts downward pressure on U.S. wages and has, almost certainly, contributed to growing wage inequality. But the effect seems modest, because trade doesn't dominate the labor market.
None of this means that we should embrace trade uncritically.
America's chronic trade deficits partly reflect the dollar's historical role as the main international currency, which has kept its exchange rate at a level that encourages imports and discourages exports.
But other countries' subsidies, currency manipulations and protectionist policies compound the pressure on U.S. producers.
We need to defend our interests without assuming that lopsided trade - and foreigners - is the source of all our problems.
All too often, the fault lies at home.