Higher prices show that our insatiable demand for gasoline is catching up with our willingness to produce it. The price of gasoline rose over the winter, but that was just the beginning of an inevitable upward trend. Summer will give us an even better feel for things to come. Complaints by motorists and accusations by politicians will not avoid the unavoidable: Most Americans simply cannot have all the gasoline they want much longer. We already burn more of this precious but cheap commodity than U.S. refineries can make. For the past two years, imports climbing toward 1 million barrels per...