A more compelling argument is that the use of military force — even of limited scope — would cause Iran to rethink one of its fundamental assumptions: That the U.S., chastened by its Iraq intervention, won’t use military force in the Middle East for any reason.

From the Iranian perspective, this isn’t a crazy conclusion to have drawn. Obama has repeatedly spoken of how the time of war has ended, of the need to nation-build at home, of how the withdrawal of U.S. forces from Iraq was one of his legacy achievements, and of the imperative to rebalance American attention and resources toward Asia. The budget sequestration, a slow-growing economy, and fatigue of the American people after a decade of wars reinforce this conclusion, while the heavy reliance on the use of drones underscores U.S. reluctance to risk American lives overseas.

Air strikes against Syrian targets, in challenging this Iranian assumption, could help address the fundamental flaw in the current effort to curb Iran’s nuclear ambitions through diplomacy. In the current context, the threat of U.S. military force isn’t credible, no matter how many times Obama declares that Iran won’t be permitted to acquire a nuclear weapon. An Iran unconcerned about U.S. military action has little incentive to come to a diplomatic compromise, given its willingness and ability to withstand the economic pain of sanctions.

In forcing the Iranians to re-evaluate the assumption that American threats of force are hollow, limited air strikes on Syria in response to proven chemical weapons use could lead to a more engaged and compliant Iran at the negotiating table.