Both countries insisted on Monday that the king’s absence was not a snub, even as it was hard to ignore four powerful factors that have led to rising tensions between the two nations: the administration’s pursuit of a nuclear accord with Iran, the rise of the Islamic State in the region, the regional unrest that came to be known as the Arab Spring and the transformation of world energy markets. An American oil boom in particular has liberated the United States from its dependence on Riyadh and changed a decades-long power dynamic…

No longer so dependent on foreign crude, the United States can flex muscles without worrying about the Saudis cutting its energy supply. Yet Washington still relies on Riyadh to keep the price of oil low to pressure Russia’s energy-based economy in the standoff over Ukraine…

But experts said the United States had little desire to be drawn more deeply into the dangerous proxy war between Iran and the Sunni states playing out in places like Yemen. “The United States is not interested in overindulging in other issues that the gulf states are worried about,” said Marwan Muasher, a Jordanian former foreign minister. “Are the gulf states going to go back from this meeting feeling reassured? I would say the answer is no.”