Continuing his fierce criticism of Vladimir Putin's job performance as Russian president, economist and New York Times columnist Paul Krugman writes today that the economic crisis confronting Russia illustrates the perils of a warmongering foreign policy -- perils, Krugman argues, that the disastrous Iraq War should have made abundantly clear."You can’t treat a modern society the way ancient Rome treated a conquered province without destroying the very wealth you’re trying to seize," Krugman explains.