The strike against the Syrian al-Shayrat Air Base south of Homs is certainly controversial but generally supported around the world. The base was used as a launching pad in a chemical weapons attack that truly does cross a “redline.” As much success as Obama had as president – and he will ultimately be described as a successful president – he did fail to act against the Assad regime and of course was never to be taken seriously again with respect to Syria after his hollow threat about chemical weapons crossing redlines. And even though like much of the world I find Trump dangerous, unstable, lazy, and uninformed I have to give him credit for taking a moral and political stance that was difficult but necessary. Up until now, Assad had been confronted with little more than empty speeches condemning the use of chemical weapons.

One of the goals of foreign policy is to get others to recalculate their cost-benefit ratios. Assad’s calculations were much in his favor because his history told him that nobody was going to do much about his behavior. He used chemical weapons last week because he calculated he could get away with it. But now Assad has to recalculate his position. In an excellent policy report from the Washington Policy Institute, Michael Eisenstadt writes cogently about altering cost-benefit ratios and the variables that factor into Assad’s thinking. You can read it here. Here is one analysis along the way to a decision about whether or not to bomb Syrian airbases and what Assad is likely to do about it.

Historically Assad has shied away from military responses when he concludes that his opposition is aggressive and determined. The Israelis have on more than a couple of occasions struck Syrian targets because their intelligence told them that weapons were being transported to Hezbollah. And although Syria has at times returned fire most of the time they do nothing. And, of course, even though Obama threatened responses after crossing “redlines” the Syrians just ignored it and used chemical weapons anyway. They calculated that Obama would not respond and their actions would reap more benefits than costs. Eisenstadt concludes the following cost-benefit ratio and the decisions that go with them. These conclusions are based on historical occurrences as well as “logical” assumptions.

(1) Assad backs down when confronted with a strong and potentially threatening proponent. (2) If Assad is unsure of how an adversary counts his costs or benefits he will test the waters but then withdraw if things appear threatening. And (3) if Assad sees no major cost to his behavior he will proceed as he wishes. Of course there are other situational and strategic factors involved but the United States is in a position to use force to maximize the likelihood that the other side will recalculate cost-benefit ratios such that they realize predictable consequences. This is the only way ceasefires will be respected and some predictability can be inserted into the decision matrix that characterizes international brinksmanship exchanges.