RIYADH, Saudi Arabia—Secretary of State John Kerry and his European allies, in their renewed drive to promote stability in the Middle East, are increasingly reliant on the two countries the U.S. has historically argued only undermine stability—Russia and Iran.

The engagement of Moscow and Tehran by the U.S. and Europe exemplifies the shifting balance of power in the region, as President Barack Obama has made clear his intent to minimize the U.S. military role there, according to U.S. and Arab officials.

But the West is taking risks by including the Russians and Iranians in diplomacy, said Emile Hokayem, a regional analyst at London’s International Institute for Strategic Studies, expressing a view that is shared by many Arab officials.

Neither country has shown that it shares the same long-term interests as Washington or European capitals. In many cases, both still actively oppose those interests. In addition, the security and alliance structure the U.S. has created over the past five decades in the Middle East is at risk of fraying, as Arab countries look to the Kremlin as much as the White House for guidance.

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