The widening in May of the U.S. trade gap between imports and exports to an 18-month high indicates clearly that Americans just don't get the economic mess the country is in.

The difference between U.S. imports, including cars, computers and clothing, and its exports to foreign countries grew from $40.3 billion in April to $42.3 billion in May, an increase of nearly 5 percent. It produced the largest chasm in that area since November 2008, when the recession was still young.

It is a reasonable position not to favor protectionism in world trade. The United States needs to respect international trade agreements and the logic that lies behind them in its foreign trade.

But to buy American is not protectionism. It is self-defense, pure and simple. One of America's really big problems is unemployment. It stands now at 9.5 percent. Nearly one in 10 Americans who wants a job doesn't have one. That is not to count the millions of underemployed -- part-time workers -- and those who have simply dropped out of the job market in despair.

It does not require a Ph.D. in astrophysics to understand that if Americans buy foreign goods instead of American-made goods that jobs are not created in the United States. But that is what they do. How many people look at the label on an article before buying it to see if it is made in the United States?

Another big economic problem is the national debt, and, in particular, the amount of that debt that is held by foreign countries. Start with China, from which an enormous amount of American imports come. Then proceed to Japan, European Union countries and the Middle East oil producers, all of whom hold billions in American debt.

Protectionism fails as a concept in its assumption that American producers have to be coddled because they are unable to compete effectively with rival foreign producers. This may be true in some fields, but there is no way to find out if American consumers are not prepared to try American products. Our auto companies were slow to understand the need and the appetite for fuel-efficient and alternate fuel vehicles. But they paid dearly for that lack of wisdom and now they do seem to get it. But now they need Americans to give their new lines a chance.

The apparent inability of Americans to link their buying habits to the clear crisis in American employment and our country's foreign debt is stunning, almost to the point of incomprehensibility. This is one of those issues that our people simply cannot afford not to understand. Buy American. Save our economy. Save your own job.

Cartoonist Rob Rogers does "Rob's Rough," an early look at his work and his creative process, exclusively at PG+, a members-only web site of the Pittsburgh Post-Gazette. Our introduction to PG+ gives you all the details.