JOHN BRENNAN:

Oh, well, it was.

Russia has had a 50-, 60-year investment in Syria. They have had military bases there, military advisers and facilities. They ratcheted up the support to the Bashar Assad regime, as the opposition gained strength and as the Syrian regime continued to be degraded by the opposition forces.

So, we could see the Russians were not going to abandon a long-term ally. They were going to invest more in protecting that ally. There have been negotiations going on to try to get the Russians and others to understand that Bashar Assad is part of the problem. He's not part of the solution.

But they decided to double down and to bring in their latest weaponry, both in terms of fixed and rotor-wing aircraft, tanks, APCs, other types of things. So they have a major investment in Syria. And the opposition was — as good as they were putting up a fight against the regime, they were fighting the Syrians. They were fighting the Iranians. They have been fighting Hezbollah, as well as the Russian military.

So the odds were stacked against them. But the Russians decided that they were not going to allow the Free Syrian Army, the opposition, that have legitimate grievances against the Assad regime to prevail. Unfortunately, the Russians painted the entire opposition as terrorists.

And that's why they undertook this very bold, and, in my mind, in many respects, reckless military action to mow down so many Syrians.