In short, the Navy has carried out the order of its commander in chief to counter Iran in the Middle East, but in the least provocative way. Just where to station the Lincoln — one of the country’s 11 nuclear-powered aircraft carriers — is a decision made by the Navy’s Fifth Fleet, which has its headquarters in Bahrain. The fear is that sending an aircraft carrier through the narrow Strait of Hormuz, right when Mr. Trump has turned up the heat on Tehran, could provoke exactly the kind of conflict the Pentagon wants to avoid.

“Anytime a carrier moves close to shore, and especially into confined waters, the danger to the ship goes up significantly,” said James G. Stavridis, a retired admiral and former supreme allied commander for the North Atlantic Treaty Organization. “It becomes vulnerable to diesel submarines, shore-launched cruise missiles and swarming tactics by small boats armed with missiles” — all parts of the Iranian arsenal of weaponry and tactical maneuvers.