During my time leading NATO global operations from 2009 through 2013 as the supreme allied commander, I spent an inordinate amount of time and effort focused on keeping the 50-nation coalition of the International Security Assistance Force on a steady course and speed in Afghanistan. In every sense, the coalition itself represented the strategic center of gravity in the complex struggle for the future of Afghanistan -- and still does.

As the NATO summit in Wales approaches, the 28 nations of the alliance should recall the words of Aldous Huxley, author of the classic 20th-century dystopian novel Brave New World: "And, of course, stability isn't nearly so spectacular as instability."

A 50-year ideological struggle, hundreds of thousands killed, millions displaced, mass graves, murder, rape, torture, a virulent insurgency threatening the overthrow of the entire social order, a rebel enclave carved out of the heart of a big nation. It sounds a lot like the Middle East today, but the grim tale of the tape also applies to the beautiful Andean nation of Colombia over the past half-century.

As ISIS consolidates its position across the Syrian and Iraqi divide, NATO must realize that it is only a matter of time before a wave of EU-passport-bearing jihadists will be headed back home to wreak havoc. Those AK-toting fundamentalists are a bit busy at the moment destroying two Shiite/Alawite regimes in Iraq and Syria, respectively, but the eye of Sunni extremism will inevitably turn its attention to the capitals of Europe. This means NATO must begin now to do all it can to undermine this potential future threat, and the key will be along the Turkish border.

"I cannot and I will not recant anything, since it is neither safe nor right to go against conscience. May God help me. Amen." —Martin Luther, reply to the Diet of Worms, April 1521