ISIS is an idea.
So was fascism.
Most instances of fascism were somewhat closer to being "a particular ethnic group" than ISIS is, and anyway he said "notoriously hard", not "impossible", and the defeat of fascism was not exactly painless and effortless.
Here's my op-ed that uses long-term orientation, probabilistic thinking, numeracy, consider the alternative, reaching our actual goals, avoiding intuitive emotional reactions and attention bias, and other rationality techniques to suggest more rational responses to the Paris attacks and the ISIS threat. It's published in the Sunday edition of The Plain Dealer, a major newspaper (16th in the US). This is part of my broader project, Intentional Insights, of conveying rational thinking, including about politics, to a broad audience to raise the sanity waterline.