The Strait of Hormuz , a narrow waterway once carrying roughly a fifth of the world’s oil and gas, remains effectively closed after the United States and Iran imposed competing blockades . Naval blockades are one of the oldest weapons in warfare, requiring no ground troops or invasion, just the ability to cut off what an enemy needs to survive. These blockades have reshaped economies, societies and alliances across generations, sometimes with instant shockwaves, sometimes with effects only seen later. Recommended Stories list of 4 items list 1 of 4 Yemen reports hijacked oil tanker headed for Somalia list 2 of 4 Syria becomes alternative energy corridor for oil as Hormuz effectively blo list 3 of 4 Why are maritime laws failing to secure the seas? list 4 of 4 Iran war: What’s happening on day 65 as Trump reviews new plan to end war?…