On the day after the barracks bombing, however, the president reaffirmed his commitment: “The reason they must stay there until the situation is under control is quite clear. We have vital interests in Lebanon. And our actions in Lebanon are in the cause of world peace.” Over a month later, on Dec. 1, Reagan stated that the Marines were in Beirut to “demonstrate the strength of our commitment to peace in the Middle East…. Their presence is making it possible for reason to triumph over the forces of violence, hatred, and intimidation.” Nine days later, he told the nation: “Once internal stability is established and withdrawal of all foreign forces is assured, the Marines will leave.” Finally, on Feb. 4, 1984, Reagan stated something frequently heard in debates over Afghanistan and other theaters of conflict today — if the United States withdraws, “we’ll be sending one signal to terrorists everywhere: They can gain by waging war against innocent people…. If we’re to be secure in our homes and in the world, we must stand together against those who threaten us.”

Yet, just three days later, on Feb. 7, Reagan ordered the Marines to “redeploy” to their ships offshore — which was actually a full withdrawal achieved in three weeks. Although the Marine’s mission in Lebanon was not clearly defined and, subsequently, not achieved, Reagan’s tacit admission of failure and withdrawal of the Marines from Lebanon limited America’s further involvement in foreign-policy disaster — saving money, lives, and time. Many pundits later claimed wrongly that Reagan was erroneous, because Osama bin Laden contended that the withdrawal was a sign of U.S. weakness; as if America’s strategic choices should be held hostage to how terrorists choose to describe them…

But historians do not make future policy decisions; they study and assess previous ones. Sending Marines to Lebanon for such an imprecise and unachievable end-state was a tremendous mistake. Reagan’s decision to tacitly admit that it was a U.S. foreign-policy failure, and to then undertake corrective actions, was an admirable trait rarely seen in poilcymakers or presidents.