Economists have few more important tasks than to dispel the misconceived notion that protectionism fosters prosperity. It doesn’t. Americans should appreciate the benefits of free trade more than others, for our 50 states trade freely with one another. Imagine how much lower your personal standard of living would be if goods or services from outside Montana carried a high tariff.

It’s counterintuitive, but demonstrably true, that the U.S. would be poorer if we closed our economy to foreign goods and services. Worse, if the U.S. were to ramp up protectionism other countries would surely follow. History teaches that the result would deepen and prolong the current recession and make the world a less hopeful and more dangerous place.

Let’s be clear—free trade creates winners and losers. A textile worker who loses his job due to cheaper imports experiences real pain. The job losses from trade tend to be localized while the benefits are spread broadly. That’s why free trade is such an easy target, especially during these times of economic hardship.

The alternative to free trade is the economic policy of self-sufficiency known as autarky. While self-sufficiency is a fine individual character trait, when employed as national economic policy, disaster and misery follow. North Korea is a prime example. Further, because autarkies prohibit imports, governments face strong incentives to grab resources through force. Japan prior to WWII is an example. Nineteenth century economist Frédéric Bastiat put it well, “If goods don’t cross borders, troops will.”

Whenever a nation erects barriers to trade, it punishes the majority of its citizens while rewarding a select few special interests. Here are some examples.

Last summer, when gasoline prices hit $4 a gallon, several high-ranking senators came out in favor of scrapping the $0.54 cent-per-gallon tariff the U.S. levies on imports of Brazilian sugarcane ethanol. Brazilian ethanol—even with the tariff—is cheaper than U.S. corn-based ethanol. For many environmentalists, Brazilian ethanol is preferable since it has fewer ecological impacts than corn-based ethanol.

But corn-belt politicians, including then-candidate Obama, of course, were strongly opposed. This raises an interesting and important question: what is the goal for U.S. energy policy? When politicians behave in such a crass manner it’s no surprise that people are skeptical of their claims regarding the dangers of global warming.

And here’s an example closer to home. When GM announced its decision to cancel its high-cost contract with the Columbus-based Stillwater palladium mine (GM wants to purchase cheaper palladium from mines in Russia and South Africa), our Governor, senators, and congressman came unhinged. But how can GM prosper without economizing on inputs?

Similar versions of this story are repeated across the nation. Massachusetts’s representative Barney Frank intervened to save a GM distribution center in Norton, Massachusetts. The plant was slated for closure but Mr. Frank put in a call to GM’s CEO and postponed the deal. Does the government really want GM to succeed, or do politicians prefer it to remain a ward of the state?

William Cockran was an early 20th Century congressman from New York. He observed, “The essential difference between Free Trade and...Protection is, that under a system of Free Trade the excellence of the product is the only means by which it can secure a market; while under Protection an inferior article can dominate the market through the aid of legislation. The necessary effect of Free Trade is, therefore, to encourage efficiency in production, while the necessary effect of Protection is to encourage skill in corruption.”

Opponents of international trade want us to believe trade is a zero sum game and American jobs are sacrificed for cheap foreign goods. But this is economic sophistry. While a dynamic, open economy creates opportunity for some and hardship for others, international trade allows us to use our resources to focus on what we do best. Prosperity and peace follow.