Once labeled a pariah, Saudi Crown Prince Mohammed bin Salman took center stage as master of ceremonies last week when Arab states readmitted Syria to the Arab League, signaling to Washington who calls the regional shots. His effusive greeting of President Bashar al-Assad at the Arab summit with kissed cheeks and a warm embrace defied U.S. disapproval at Syria's return to the fold and capped a turnabout in the prince's fortunes spurred by geopolitical realities.