Since February, the United States has been applying military and political pressure to Iran to force terms akin to a surrender. Six months later, and despite the White House bombast, there has been no agreement, and international shipping through the Strait of Hormuz remains vulnerable to Iranian attacks. With talks seemingly drifting, Washington now appears to have moved to Plan B: tightening the financial noose. The aim is to make Iran’s continued resistance so economically costly that it is forced to reconsider.

Exerting maximum economic pressure on Tehran would risk blowback from Beijing.

The United States is preparing a new sanctions campaign against Iran as Tehran threatens to stop oil exports from the Gulf and retaliate against countries that support Washington.…