The U.S. trade deficit rose in January, according to this morning’s monthly trade report from the U.S. Commerce Department, and on cue the news is being greeted as a bad omen for the U.S. economy.

Reflecting the conventional wisdom, this morning’s Associated Press story states as a matter of fact, with no attribution:

A widening trade deficit hurts the U.S. economy. When imports outpace exports, more jobs go to foreign workers than to U.S. workers.

Oh really? As I’ve documented elsewhere, the U.S. economy actually grows faster during periods when the trade deficit is widening compared to when it is shrinking. That’s because an expanding economy increases demand for imports as well as domestically made goods. Stronger growth also attracts more foreign investment, which is the flip side of the trade deficit.

The same story is true for jobs. In Chapter 5 of my 2009 Cato book, Mad about Trade, I show how the unemployment rate invariably rises during periods when the trade deficit is “improving,” and declines during periods when the deficit is “worsening.” (Check out Table 2.2 on p. 81, courtesy of Google Books.)

Just think back to the 1990s. From 1992 to 2000, the trade deficit widened from 0.5 percent of GDP to 3.9 percent. During that same period, the unemployment rate fell from 7.3 percent to 3.9 percent and the economy added more than 18 million jobs.

More recently, the trade deficit narrowed sharply between 2007 and 2009 as a share of GDP, while the economy lost more than 8 million jobs and unemployment soared.

The conventional wisdom on trade deficits and the economy is due for a reality check. If politicians believe that “a widening trade deficit hurts the economy,” contrary to all the evidence, they will be more tempted to reach for the snake oil of protectionism.