National Journal - 
They peg the total economic costs of both wars at $4 trillion to $6 trillion, Bilmes says. That includes fallout from the sharp increase in oil prices since 2003, which is largely attributable to growing demand from developing countries and current unrest in the Middle East but was also spurred in some part by the Iraq and Afghanistan conflicts. Bilmes and Stiglitz also count part of the 2008 financial crisis among the costs, theorizing that oil price hikes injected liquidity in global economies battling slowdowns in growth—and that helped push up housing prices and contributed to the bubble.What do we have to show for that tab? Two wars that continue to occupy 150,000 troops and tie up a quarter of our defense budget; a bloated homeland-security apparatus that has at times pushed the bounds of civil liberty; soaring oil prices partially attributable to the global war on bin Laden’s terrorist network; and a chunk of our mounting national debt, which threatens to hobble the economy unless lawmakers compromise on an unprecedented deficit-reduction deal. All of that has not given us, at least not yet, anything close to the social or economic advancements produced by the battles against America’s costliest past enemies.
As we mark Osama bin Laden’s death, what’s striking is how much the cost our nation - and how little we’ve gained from our fight against him. By conservative estimates, bin Laden cost the United States at least $3 trillion over the past 15 years, counting the disruptions he wrought on the domestic economy, the wars and heightened security triggered by the terrorist attacks he engineered, and the direct efforts to hunt him down...
