Daniel Bessner in the Boston Review:
On February 2, 2003, the political scientist John J. Mearsheimer published a co-authored op-ed in The New York Times that lambasted the Bush Administration’s case for invading Iraq. In a carefully laid out argument, Mearsheimer and Stephen Walt, a fellow scholar of international relations, predicted that deposing Saddam Hussein would cause more problems than it solved. They argued that the dictator needed to be contained, and that preventative war was not just unnecessary, but harmful.
Of course, neither Bush nor his cronies listened, and on March 20 the Iraq War began. When it was officially wound down in December 2011 (note that we still retain thousands of U.S. troops in the country), it had cost almost $1 trillion; resulted in the deaths of hundreds of thousands of Iraqis and about 4,500 U.S. soldiers; generated untold suffering amongst people who lost limbs, family members, and their mental health; and destabilized the region by empowering the Islamic State and engendering a massive refugee crisis.
More here.