President Trump showed great ignorance on Tuesday when he stated, "Because of the fact that [Turkey] bought a Russian missile, we’re not allowed to sell them billions of dollars worth of aircraft. It’s not a fair situation."

Sorry, Mr. President, it is both fair and necessary.

Far more is at stake here than a few billion dollars. What's truly at stake is two-fold: the ability of NATO aircrews to operate against Russian air defense networks and the responsibility of NATO member states to support the alliance.

On the first point, NATO aircrews already face a significant challenge in the face of S-400 and other Russian air and missile defense systems. The S-400 is a superb platform designed explicitly to deny fifth-generation NATO warplanes access into Russian strongholds. The range and tracking capability of the S-400 means that it also offers Russia the potential to launch rapid blitzkrieg-style attacks into Eastern Europe and then hold that territory under air defense protection. This is a critical threat to NATO, particularly Estonia, Latvia, Lithuania, and Poland.

This is bad enough.

Yet, if the Turks start operating their F-35s alongside the S-400, the Russian intelligence services will truly hit the jackpot. Operating undercover as trainers for the Turkish crews who will operate the S-400, or hacking into the S-400 software through back doors, the Russians will gain critical intelligence on how to search for, identify, and target the F-35. That intelligence will then inform Russian tactical doctrine.

This poses a totally unacceptable threat to the NATO aircrews destined to operate the F-35. It also introduces a totally unacceptable degradation of NATO combat potential.

Had President Trump listened to his intelligence briefings more closely he would know this. Instead, the president absurdly seems to think this is a lost business opportunity.

But Trump gives Turkish President Recep Tayyip Erdoğan far too much sympathy. Erdoğan knows the S-400 purchase is incompatible with his NATO responsibilities, but he continues anyway, thinking that he can play Trump for a fool.

Trump has got to wake up.