With even the existing agreements on the Strait of Hormuz subject to conflicting interpretations, Gulf powers feel compelled to forge their own relations with Iran, fracturing the united front the U.S. has sought to build. It is doubtful whether Rubio's visit can mend the unraveled trust – and Iran could gain diplomatic leverage in the talks

The US seeks to balance reassurances to allies without undermining its new engagement with Iran

Gulf Arab leaders are expected to press Marco Rubio over a draft Iran agreement they fear could reshape regional security and boost Tehran’s power.

Gulf states press Washington on security concerns after landmark Iran peace accord