Iran’s strike on Israel has again underscored the urgent need for America to restore deterrence. Iran, Russia, Communist China, and their allies must again grasp that their malign actions will be met with intolerable consequences. That a credible threat of American escalation, with Washington poised to act, exists. Yet as long as President Biden is in office none of this is likely. It is not even clear if deterrence is the administration’s aim.

“Don’t” is not a deterrent. Neither is defense. While it’s a relief that Israel’s layered missile defense system intercepted most of the more than 300 drones and missiles, this is not cause to “take the win,” as Mr. Biden told Prime Minister Netanyahu. Iran should not have felt itself emboldened to attack Israel. Nor Russia, Ukraine, and China to flare tensions in the South China Sea. Yet they do as they view America as too timid to act.

We must quickly reverse course. This entails reintroducing a range of measures that would compel our adversaries to reassess their objectives and the perceived costs of achieving them — measures largely neglected by the Biden Administration. First, we’d need to revisit the fundamentals of hard power, central to which are enhanced military capabilities and a robust defense industrial base. A threat lacks credibility if it cannot be executed.