Formally, at least, no decision has been made, but the writing appears to be on the wall: The United States is considering pulling out security personnel and assets from West Africa. It's a decision that is ratcheting up anxiety in Paris as French defense planners ponder the consequences of a U.S. pullout, particularly from the security-plagued Sahel. Already, senior French security officials, including Defense Minister Florence Parly, have vowed to go to Washington to try to discourage the Americans from withdrawing by reminding them that France supports U.S. efforts in other regions, like the Horn of Africa and the Middle East. Yet while the French may have some allies in the U.S. Congress, Department of Defense and the Department of State, the Trump administration is likely to push forward with its plan to shift personnel and assets elsewhere to better counter Russian and Chinese influence. That, in turn, could leave...