Gregory Mankiw, who heads the White House Council of Economic Advisors, ignited a firestorm of debate this month when he said outsourcing of U.S. jobs is probably a good thing in the long run. As tends to happen with hot-button issues in presidential election years, sensible discussion of this question soon was drowned in an uproar of political posturing. John Kerry and John Edwards — who are seeking the Democratic nomination to take on George W. Bush in November — denounced the government’s so-called conspiracy to ship jobs overseas. Even Dennis Hastert, the Republican speaker of the House, criticized Mankiw. In the past few days, other respected economists — such as Columbia University’s Jagdish Bhagwati — have come under fire when they tried to explain the economic rationale behind outsourcing.   Politics apart, the reality is that outsourcing is as old as the corporation.…