America screwed the pooch by aligning ourselves in a love/hate relationship with radical islam since the cold war thanks to our wonderful CIA. Each President since the 70's has supported at times and opposed involvement with radical islam.  Bush did create a vacuum and Obama tore the filter off.  The only way to stop this trend is to discontinue providing the resources and motivation for terrorists to attack America. Multiple arms transfers have supplied Syrian 'rebels' to overthrow their government, this happened under Obama. When Isis took Mosul we pretty much handed them over 2,000 Humvees, in Ramadi we provided ISIS with M1A1 Abrams.  In 2015 the Pentagon requested 1.3B$  in weapons for the Iraqi government, and over 20M$ for the 'tribes' . Terrorism is a symptom and American imperialism in the Middle East is the cancer.  U.S companies made over 130B$ from the Iraq war, if Hillary is President this trend of politics,favors,and imperialism will continue.