Welcome to The Adversarial. Every other week, we’ll provide you with expert analysis on America’s greatest challengers: China, Russia, Iran, North Korea, and jihadists. Read more below.***IranSenior officials from Iran, Oman, and neighboring Gulf states were scheduled to meet in Salalah on Monday to unveil the provisions of a deal for managing the Strait of Hormuz. Those plans unraveled before the meeting could take place, and Oman’s foreign minister announced a postponement.For Tehran, securing buy-in from U.S. allies in the Gulf was potentially a step toward resuming negotiations with Washington — presenting the Trump administration with a fix, even if temporary, to the closure of the strait, which was one of the central issues the June memorandum of understanding between the two sides had intended to resolve. The difficulty of forging a common position with littoral states highlights the greater challenge of securing U.S. acceptance of a potential deal over the strait, especially when the Trump administration has been stepping up efforts to undermine Iran’s hold over the waterway.Those efforts to help protect shipping through the strait have yet to translate into easing oil prices. Iran’s partners in Yemen, the Houthis, captured additional territory along the Red Sea in the last week, strengthening their ability to threaten Saudi shipping through the Bab al-Mandeb Strait. Attacks on Saudi energy facilities from pro-Iran militias in Iraq added to market volatility. With its threats in Hormuz and its partners’ abilities to undermine Saudi Arabia’s oil exports along other routes, Iran is clearly demonstrating its capacity to force economic pain on the world in response to U.S. moves. However, Washington has shown few signs of backing down, and Tehran’s leadership appears united in the belief that using leverage over the strait is the best way forward. The world is likely to experience continuing instability in oil