STEVEN SIMON:

Well, I think the U.S. will probably want to avoid that.

Look, the Russian deployment, I think, will have a military effect if it's carried out. More importantly, it will have an effect on the cohesion of the Syrian regime. Those members of the regime who the United States was perhaps hoping to peel away from Assad in pursuit of a transition scenario will now feel that, you know, the regime has a major power in its corner, in addition to the Iranians, who are now perhaps more able to act on behalf of the regime with the nuclear issue off the table.

So I think, you know, this does put the regime, the Syrian regime in a stronger position. This isn't something that the United States really, I think, has the leverage to deal with effectively, really to counter. The administration has two choices. And maybe this is a bit of an exaggeration. It's a dichotomy.

But, on the one hand, if you can't beat them, join them, so find a way to cooperate with the Russians, pull them into an anti-ISIS coalition, coordinate airstrikes and direct the Russian effort in that direction. The alternative, really to try to block this Russian move entirely, is going to be very difficult, in part because, as the other speaker said, the Russians have plenty of other options for getting this military equipment, military assistance into Syria.

It's not something the U.S. can block by playing a game of Whac-A-Mole with various countries whose airspace the Russians need to rely on.