Iran would enjoy a range of options to respond to the U,S. attacks. Iran could step up efforts to destabilize Iraq and Afghanistan through the use of proxies and arms shipments. Similarly, it could try to induce its proxies in the region to attack U.S. allies. Iran could use its extensive fleet of ballistic missiles to attack U.S. bases, ships, and the military and economic installations of U.S. allies, although this missile force would represent a depreciating asset as its numbers declined over time. Most likely, however, is that Iran could simply wait, under the logic that international opinion against the U.S. campaign would steadily build until Washington could no longer maintain its belligerence.
(This first appeared in October 2017).
The Trump administration appears ready to decertify Iranian compliance with the the Joint Comprehensive Plan of Action (JCPOA), despite a lack of evidence of Iranian violations. For critics of the JCPOA, this represents a move in the right direction; the goal of U.S. policy should be the end of the Islamic Republic and the overthrow of the existing regime in Tehran. As long as this regime exists, no matter how constrained it is by bilateral and multilateral agreements, it will seek to undermine the stability of the established order in the Middle East through overt and covert military means. This position is held in the United States by figures such as Mark Dubowitz [3] of the Foundation for Defense of Democracies and by policymakers such as Sen. Tom Cotton [4]. The desire for regime change is also shared by some in the Middle East, including significant elements of the Israeli and Saudi national security states.
To be fair, few of these voices have called for a military campaign to overthrow the Islamic Republic, and generally for good reason; there is little prospect for success and little appetite for paying the costs necessary to succeed. Still, it’s worth evaluating what a war for regime change might look like. The decision of the Bush administration to commit itself to regime change in Iraq undoubtedly helped lead to the war, even if war was not initially the intention. If the Trump administration similarly commits itself to regime change, then war may come sooner or later.