We don’t know if or when the United States is planning a retaliatory strike against chemical weapons stockpiles in Syria, but all the signs are there. U.S. officials are in talks with France and Great Britain, reportedly discussing a response. The Harry S. Truman carrier strike group is heading for the Middle East. European commercial airlines have been warned about a possible strike in that region. White House insiders are saying that President Trump wasn’t happy with the results of the first airstrike on Syria and is asking his military advisers about a more robust attack.

Trump has done it before and there’s no reason to think he’d be bashful about responding this time. But now there are new players in the game, specifically the Russians. They formerly restricted their response to such foreign attacks by the United States to verbal condemnations at the UN or negative press releases. Today they have a very physical presence in Syria, with both troops and military hardware. Putin is openly allied with Bashar al-Assad and that partnership has given the Russians their first warm-water naval port (in Tartus) in living memory.

This has led Vladimir Putin to make a far more serious threat this time around. This week the Russians put the word out that if we launch another strike on Syria, they will be looking to shoot down any incoming missiles and, more disturbingly, launch their own counterstrike on “the source” of the incoming missiles. That would be our carrier groups and submarines. (BBC, emphasis added)

“I would once again beseech you to refrain from the plans that you’re currently developing,” Moscow’s UN envoy Vasily Nebenzia said.

He warned Washington that it will “bear responsibility” for any “illegal military adventure” it carries out…

Several senior Russian figures have warned of a Russian response to a US attack. Alexander Zasypkin, Moscow’s ambassador to Lebanon, is the latest, repeating a warning by the head of the military that missiles would be shot down and their launch sites targeted.

The Russians are talking about more than a strongly worded letter here. And having put that statement out for all the world to see, Trump and Putin may be talking themselves into a corner. Obviously, President Trump feels entitled to hit Syria over their use of banned weapons and may seek the support of our allies in deploying a considerably more forceful attack than last time. But what if the Russians start shooting back? If they “only” shoot down some of our cruise missiles, that’s problematic enough. It would stymie our efforts to some degree and also reveal whether or not Russian military technology is up to the task. (Analysts believe that the Russian S-400 air defense system, which they have deployed in Syria, is capable of possibly repelling a cruise missile attack but it’s never been put to the test in the real world.)

So how did the President respond to this? Not very subtly.

Of course, that’s just a taunt on Twitter, so it may or may not indicate actual policy. The Russians will pay attention, of course. But what if they shoot down one of our planes or actually launch on one of our surface ships or subs? That’s an act of war which would demand some sort of retaliation or risk having the United States look as if we were running home with our tail between our legs. I rather doubt either side wants to see the newly revived cold war turn hot so quickly, but what are the alternatives? At this point, if Trump backs off and fails to hit Syria he winds up looking timid and meek. But now that the Russians have made the threat, can Putin afford to not follow through and wind up looking like a paper tiger?

We shouldn’t underestimate the serious nature of the precipice we’re standing at right now. Hitting Assad over his use of chemical weapons is one thing. Getting into an open naval or air battle with the Russians takes it to a new and dangerous level. And if we do exchange fire with Russia it will require some extraordinary diplomacy to walk everyone back to their respective corners.