Using bombing to "send a message" rather than achieve a specific and realistically achievable military purpose is not a new idea. It was tried in Vietnam. The Onion, as often happens, gets to the point: "Experts Point To Long, Glorious History Of Successful U.S. Bombing Campaigns." The late Robert McNamara was a pioneer of the idea of bombing as message-sending, and eventually realized his error. The other side had a clear objective, and took Saigon.
A case can be made, I think, for staying out of the Syrian affair altogether, and a case can be made for going in and changing the situation on the ground. But a middle ground that accomplishes little but to make us feel better? The worst of all possible worlds.