President Obama has, at long last, publicly called on Col. Moammar Qaddafi to end his 42-year tenure as dictator of Libya.

The fact that the president has waited so long to make any public gesture in this direction, and the forum in which he addressed Qaddafi—a joint press conference with the president of Mexico—surely detracts from any power his words might have carried. So, too, does his reasoning: Qaddafi, says Obama, “has lost the legitimacy to lead”—a phrase which combines turgid language with the implication that Qaddafi, who staged a coup d’état and has exercised dictatorial power since 1969, was ever Libya’s “legitimate” leader. Informing Qaddafi that he has lost the “legitimacy to lead” lacks the unambiguous impact of Cromwell’s famous rebuke to the Long Parliament—”Depart, I say, and let us have done with you. In the name of God, go!”—but at this stage in the protracted Libyan struggle, it is better than nothing.