Mr. Trump isn't the first to associate the Obama-Clinton Middle East Policy history as being the manure of growth for the growth of ISIS. Spreading anarchy and chaos liberating Libya's guns and explosives and supplying terrorists with weapons to subvert the lawful Syrian Government all helped support the rapid rise of ISIS. Many left-leaning McGoo publications find Mr. Trump's assertion preposterous and laughable.
http://www.thedailybeast.com/articles/2016/08/11/trump-s-new-conspiracy-spew-obama-founded-isis.html
http://www.thedailybeast.com/articles/2016/08/11/trump-s-new-conspiracy-spew-obama-founded-isis.html
The Obama-Clinton axis of Muslim support in Middle-East policy was an accellerant thrown onto the refugee flood to Europe that helped advance ISIS terrorism. Reality isn't always the preferred narrative of the left that support globalist candidates trying to concentrate wealth and downgrade average Americans. When the globe decides the U.S. Government can no longer operate at a tremendous loss (no balanced budget), and it tightens up, those the left expect support from will be those most harmed.