Nobel Laureate George Akerlof uses this edifying quote from Thomas Jefferson to good effect in his foreword of Hossein Askari's excellent read, Conflicts and Wars: Their Fallout and Prevention (Palgrave MacMillan, New York, 2012). Indeed, Prof. Akerlof has this to say about Askari's work:

Professor Askari begins by surveying the burden of military expenditures and of conflicts and wars. Their dollar expenditures, which are close to 15 percent of global GNP, exceed the cost of our financial crisis, of global warming, and what would be required for worldwide poverty reduction.

…He bases his approach on three interrelated propositions: aggressors do not pay the full price of their aggression; governments will do nothing to change this state of affairs on their own; and, as a result, the process of reducing conflicts must originate in the private sector.

The U.S. shouldered a heavy load in the Iraq War, to the tune of $2.4 trillion from 2003-2011. As depicted in the chart below, the $2.4 trillion U.S. tab accounted for over 75% of global expenditures in the Iraq War.