There are many strange elements in the current debate over illegal immigration, but none stranger than the mostly ignored role of Mexico. Are millions of Mexican citizens still trying to cross the U.S. border illegally because there is dismal economic growth and a shortage of jobs in Mexico? Not anymore. In terms of the economy, Mexico has rarely done better, and the United State rarely worse. The Mexican unemployment rate is currently below 5 percent. North of the border it remains stuck at over 7 percent for the 53rd consecutive month of the Obama presidency. The American gross domestic product...