Bangladesh, Sept. 20 -- The war between the United States and Iran appears to have entered a more dangerous phase, with the conflict increasingly extending beyond direct military confrontation into a wider struggle over energy supplies, maritime routes and regional security. After nearly seven months of fighting, what once looked like a prolonged stalemate is beginning to evolve into a contest over who can exert greater pressure on the international economy.

The Strait of Hormuz remains at the center of that confrontation. The waterway is critical to global energy markets, carrying a substantial share of the world's oil and liquefied natural gas. Recent maritime tracking data showed vessel crossings falling to only four on Sept. 15, far...