"I respect anyone who makes difficult and dangerous decisions out of economic necessity — whether they are public school teachers, construction workers, economic migrants, or young soldiers," the professor said at the time. "What I don't respect is a brutal invasion and occupation of Iraq that has not made our world any safer — a war that has taken advantage of economically disadvantaged Americans, a war that has given the world ISIS, and a war that has wrought carnage like that seen in Mosul and elsewhere."