Andrew McCarthy of National Review Online examines the response to Iran’s latest attack on American interests.

You could set your watch by it. Whenever there is an atrocious attack on the United States or Israel, if transnational progressives are not subjecting us to the “escalation” drivel, they are subjecting us to the “proportionality” drivel.

For about the millionth time, the law-of-war concept of proportionality does not hold that a response to an attack has to be on the same scale as the attack itself. Several Biden supporters are making that case regarding Iran’s killing and wounding of our troops in Jordan (otherwise, you see, there could be . . . escalation). Think how absurd that is: A rabid enemy aggressor gets both to attack you first and to dictate the scope of your response.

That, of course, is not how proportionality works.

The driving question in a proportionality calculation is: What is the military objective? If that objective is legitimate (which, under the United States Constitution, we get to decide for ourselves), then the use of force must be reasonably proportionate to what is required to achieve the objective. If the objective is to end or drastically diminish the aggression of Iran and its proxy forces, then a proportionate use of force would be whatever is necessary to break the enemy’s will to continue (and even escalate) that aggression.

In April 1988, after Iran mined the Persian Gulf to paralyze commerce and security traffic, one of these mines detonated and nearly sank the USS Samuel B. Roberts, a guided-missile frigate, as it was escorting Kuwaiti oil tankers. President Reagan responded with what became known as Operation Praying Mantis, combined surface-ship and air attacks that destroyed much of Iran’s navy. As described by retired U.S. Navy captain William Luti in a Christmas Day Wall Street Journal op-ed, the operation remains a case study in effective deterrence.