Set aside for a moment the enormity of Iran’s clerical tyranny having murdered tens of thousands of unarmed citizens. Even then, thinking only of America’s national security interests, without considering the moral imperative to stop a historic massacre and punish the perpetrators, it is nevertheless imperative that President Donald Trump should intervene with the U.S. military. In truth, he has already committed himself to do so, to punish the ayatollahs and help Iranians liberate themselves from nearly half a century of tyranny. The question now is whether he will keep his word or will try to find a way to abandon it. The latter course, which seems less likely, would undermine the nation he leads and betray a tyrannized people begging him to act. Trump made his commitment before sending what he called an “armada” to the Middle East, where it is now in position to pound America’s declared enemy. He made it when he deliberately and repeatedly used the term “red line” to demarcate the limit of American tolerance as Tehran sought to end a popular uprising. The line he drew was at the slaughter of Iranian civilians, and the mullahs manifestly crossed that line. A frame from a video circulating online after protests in Iran shows protesters’ bodies at a morgue in Tehran, Jan. 12, 2026. (Akasbashi/SIPA/Newscom) The president’s choice to draw his line and his readiness to refer to it again and...