If there were ever any doubt, the diplomatic wrangle over the war in Syria proves that American unipolarity was a thing that could never be. In spite of its continuing military superiority to the rest of the planet, the US is still short on soft power, the sort of moral authority that the 19th-century Pax Britannica did enjoy.
One rather shopworn explanation for the recent American inhibition in the Middle East is that of neo-isolationism, that recurrent illness of the US body politic, which, after a phase of expansionism, now prefers to settle back behind the impregnable barriers of the oceans. This was what happened after the victory of the Entente in the Great War, and if the phenomenon could not repeat itself after World War II, it was because Germany had to be reinvented, extirpating what was left of Nazism. But now the hankering to stay at home stems from different reasons. The US has lost a war in Iraq, with the corollary of a substantial improvement in the position of Iran, and a far from optimistic prognosis for the Afghan adventure.
Moscow and Washington used to share a world hegemony called bipolarity. But lately, lacking one of the two Atlases that sustained it, the system has become inherently unstable, and the present return of Moscow, architect of the possible pacification of the Syrian conflict, not only rebuilds this bipolarity, but also makes way for a certain multipolarity. As long as the US and the USSR were in opposed ideological camps, nuclear war being unthinkable, their mutual interest was to "close" the geopolitical space, without winners or losers. Today, however, the porosity of a geopolitical landscape free of ideological divisions allows for more fluid alliances. Russia thus sets foot in Asia once again, without the need to promote the good gospel of Marxism-Leninism. What a relief for Moscow, to shrug off that burden!
Should the Russian-American plan lead to the destruction of the Syrian chemical arsenal, the result will be catastrophic for the opposition
Should the Russian-American plan indeed lead to the destruction of the Syrian chemical arsenal, the result will be catastrophic for the disunited Syrian opposition, which was begging for some action of punishment from Washington to arrest the progressive erosion of its military position. President Bashar al-Assad will, in consequence, be strengthened in spite of the liquidation of his arsenal, because he is better off without chemical weapons than with them, there being a risk inherent in their mere existence, whether he uses them or not.
Iran, too, is in a better position because the indefinite suspension of American bombing renders a similar operation against Tehran all the more unlikely. And Israel may well feel that it is ahead of the game, because any action against the Syrian regime would threaten a government that guarantees, in what is a de facto alliance, a state of peace along the common frontier with the Zionist state.
The spectacle offered by Obama's diplomacy, with his corrections, rectifications and about-turns on the desirability of hammering Syria, has been a sorry one; but he may to some extent save face with the argument that the mere threat of missiles has been enough to oblige Damascus to renounce chemical warfare. And the fact that China is in no position to substitute the US at the summit of world power is underlined by the modest role it has played throughout the crisis, glad to leave everything to Russia. Only in the Asian Pacific does Beijing aspire to keep Washington at bay. But the great winner has been Putin's Russia, which, apart from its role as executor-of-the-will in the conflict, has done the US a second big favor (the first having been keeping a muzzle on Snowden concerning Washington's cyberespionage), with the pact that relieves Obama from facing a vote in Congress which, had it gone against him, would have shattered his prestige.
The American historian Immanuel Wallerstein sums up in a few words the consequences of a crisis that is only beginning: "The US lacks power to enforce its mandates." This is multipolarity.