As presidential candidates debate strategies for defeating ISIS, now might be a good time to rerun the above video clip from Showtime's terrorism show Homeland to cut to the heart of the matter.

A little background: in the opening episode of Homeland's Season 5, CIA agent Peter Quinn delivers a speech that stands out as uncommon sense about the clash of civilization and barbarism.

In the clip, Quinn (actor Rupert Friend) is introduced to a roomful of important people as an agent on the ground in Syria for two years, including in Al-Raqqah, the de facto capitol of the Islamic State. When asked if our side's strategy is working, Quinn asks, "What strategy?" No one is able to answer, and Quinn points out that therein lies the problem. ISIS has a strategy which includes beheadings, crucifixions, and the revival of slavery, and it all derives from "their f*cking book, the only book they ever read."

"They're there for one reason and one reason only," he continues, "to die for the Caliphate and usher in a world without infidels. That's their strategy and it's been that way since the 7th century."

Asked what he would do, Quinn suggests 200,000 soldiers on the ground and an equal number of doctors and teachers. Told that that is not feasible and asked for another solution, Quinn says, "Hit reset -- pound Raqqah into a parking lot."

Now that's a strategy.