Iranian gunboats made a pointed move in the Strait of Hormuz this week, approaching a U.S.-flagged oil tanker in what U.S. and British maritime security sources describe as a failed attempt to interfere with the vessel’s transit. No shots were fired, the tanker continued on its way, and no damage was reported—but the message was unmistakable. The incident comes as tensions between Iran and the United States simmer just below the boiling point, with Washington continuing to reinforce its military presence in the region and Tehran looking…