This week President Bush will meet with Mexican President Vicente Fox to discuss a number of thorny issues, primary among them: immigration and border control policy. George W. Bush has long been supported a pro-growth, pro-freedom immigration strategy and clearly sees immigrants as assets to the United States. On this issue, his world vision collides with the Republican Party's more nativist faction, which would drape a "No Admittance" sign over the Statue of Liberty. On the economics of immigration, Mr. Bush is more right than his critics. Whether skilled scientists and engineers in Silicon Valley or the migrant laborers who...