When Vladimir Putin took the reins of power in a post-Soviet Russia in shambles a quarter-century ago, he immediately set about restoring Moscow's status as a global power. It took 15 years, but Russia heralded its military intervention in the Syrian civil war as proof of its return as a force to be reckoned with on the international stage. Moscow leveraged that image to expand its influence throughout the Middle East and beyond as a counterweight to the West. Now, the fall of the government of President Bashar al-Assad, a key ally of Moscow, has dealt a serious blow to...