Brown also argues that free trade depresses U.S. wages. But the much-hyped lag in wage growth probably has more to do with the business cycle. As the job market tightened, inflation-adjusted earnings have risen 2.2 percent from a year earlier. The stagnation in wages has been exaggerated, in any case. When benefits are taken into account, total inflation-adjusted compensation has risen 10 percent since 2000.

Finally, Brown blames the decline in U.S. manufacturing on free trade. This decline, however, represents a long-term trend, comparable to the decline in agricultural employment throughout the 20th century. As long as the economy is vibrant, workers in a sagging sector find employment in another. This is painful for those workers, but a reactionary parochialism shouldn't be permitted to put their interests above those of the economy as a whole, which benefits from free trade.

There are tangible benefits that Brown's opponent, Mike DeWine, notes. In Ohio, 30 percent of the state's agricultural products get exported and a quarter of its manufacturing jobs depend on exports. More broadly, free trade lowers prices for consumers, alleviating the alleged "middle-class squeeze." It increases efficiency through the fires of competition. It's no accident that one of world's most open economies is also one of the fastest-growing.

Unfortunately, Brown represents a trend. As Jonathan Martin, political writer for National Journal's The Hotline points out, many Democratic senatorial candidates share Brown's views on trade, so the traditionally free-trade Senate will soon be more protectionist. That's bad news for the economy, but maybe, just maybe, through dampening America's growth, Democrats will reduce the hated trade deficit.