U.S.-Iran Deal’s Vague Language Comes Back to Haunt Peace Efforts

The vagaries and general language that U.S. negotiators agreed to in their interim cease-fire agreement with Iran appear to be coming back to haunt them, less than two weeks after the two sides signed the deal.

That much is clear from the surge in violence over the last 72 hours, which began on Thursday when Iranian forces struck a container ship passing through the Strait of Hormuz, a vital waterway for shipping oil and natural gas.

The memorandum that the two sides agreed to calls for Iran to “make arrangements using its best efforts for the safe passage of commercial vessels” through the Strait of Hormuz for 60 days. Crucially, it leaves “arrangements” and “best efforts” undefined.

Iran appears to have interpreted that language to mean that it can determine which route ships must take. Hours before its attack on the container ship, Iran had warned ships that the only route through the strait was through its waters, trying to stop vessels from using an alternate, U.S.-backed route on the southern side of the strait that hugs the coastline of Oman.

The Iranian logic seems to be “that allowing traffic to flow freely on a route Iran neither designated nor controls would erode Iran’s main leverage,” said Hamidreza Azizi, an Iranian security expert at the German Institute for International and Security Affairs, in a social media post on Friday. “It would establish, in operational terms, that the strait can be transited without Tehran’s permission.”

The United States retaliated late Friday against the cargo ship attack, striking Iranian missile and drone storage sites and coastal radar facilities. Hours later, Bahrain reported that it had come under attack from Iranian drones.

The back-and-forth threatens to derail an already fragile pause in the fighting between the two sides, even as they are supposed to be settling many of their differences — and fleshing out the uncertainties of the initial agreement — at the negotiating table.

It also raises questions about claims made this week by Vice President JD Vance in an interview with UnHerd, in which he said a channel had been set up between the Iranian and U.S. militaries aimed at de-escalating the conflict.

A spokesman for the Islamic Revolutionary Guards Corps quickly denied that any hotline had been established regarding the strait, calling it an “absolute lie.”

“The Strait of Hormuz is Iranian territory and has no connection to the United States,” the spokesman, Hossein Mohebbi, said on social media.Iranian officials in both the civilian government and the military have asserted that, postwar, the country will manage traffic in the Strait of Hormuz, though some officials have said they will do so in conjunction with Oman, which sits across the strait. Iran has asserted a right to charge ships for passage through the waterway, saying the levies would not be tolls, but fees for unspecified services.

That is opposite from the position taken by the United States. Secretary of State Marco Rubio said this week that “no country” could charge ships for passage through the strait.