When Israeli Prime Minister Benjamin Netanyahu raises his voice on Thursday at the United Nations General Assembly against the ayatollahs in Tehran and the nuclear agreement that was recently concluded with them, he will sound, ipso facto, like yesterday’s man. In the wake of the agreement and under the auspices of Vladimir Putin, Iran has been cast in a leading role in a renewed, Russian-led campaign against Islamic State.

Taking a page from Netanyahu’s rhetorical stylebook in his own speech to the General Assembly on Monday, Putin even cast the ISIS jihadists as the true latter-day Nazis, replacing the Iranians who had previously played that role.

Netanyahu will discover that the nuclear Joint Comprehensive Plan of Action (JCPOA) is a done deal and that the battle against it is over, other than in the minds of campaigning Republicans. To deepen the prime minister’s disorientation, President Obama didn’t mention Israel or its conflict with the Palestinians even once in his own address to the General Assembly. Some Israelis who have long claimed that the West inflates the importance of their conflict with Palestinians will have to deal with withdrawal pangs now that they’re being ignored altogether.

Netanyahu will face a new reality that continues to change even as he makes his way to New York. The fight against Islamic State is now the only game in the global town. In a blitzkrieg of decisive diplomatic and military maneuvers, Putin has adroitly seized on the American reluctance to reengage in the Middle East and on the growing Western fear of hordes of refugees streaming into Europe from war ravaged Syria in order to appoint himself as leader of the good guys fighting the bad guys. Even if the Russian president is merely trying to deflect attention from his growing troubles at home, as some analysts maintain, or even if he is destined to get bogged down in a Middle East morass, as some experts predict, on Monday, in New York, he was the man of the hour, the star of the show.

Putin’s even rubbed it in in his seemingly innocuous praise for the February 1945 Yalta Conference, in which final arrangements for the United Nations were laid out 70 years ago. The historical allusion was not only meant to sting Obama for its venue in Crimea, which is still a major bone of contention between Russia and the West; the Yalta Conference was marked by the total dominance of then-Soviet dictator Joseph Stalin, basking in his military triumph, over the dying Franklin Roosevelt and the depleted Winston Churchill. It paved the way for the eventual Soviet domination over Eastern Europe, providing a historical precedent as well as a role model that Putin would love to emulate.

Given the difficult circumstances, Obama apparently decided that his best defense would be to go on the offense. He savaged Putin, albeit indirectly, brandished his diplomatic achievements in Iran and Cuba and praised dialogue, diplomacy and the strength of democracy. Leaders who fear their own citizens, Obama said with a wink at Putin himself, are bound to fail.

Although Washington was reportedly taken aback by Russia’s swift military buildup in Syria, its secret intelligence-sharing deal with Iraq, its behind the scenes coordination with Iran and Putin’s new proposal for a P5+1 type forum that would oversee the fight against ISIS, it was on the issue of Bashar Assad that Obama confronted Putin most directly and publicly. Assad must go, he said.

Nonetheless, even Obama agrees to a “managed transition” for the Assad regime, presumably after Islamic State has been defeated.

To Putin’s credit, therefore, he seems to have put an end to the bi-polar strategy pursued by the West until now, which, to paraphrase what David Ben-Gurion once said of fighting the Nazis and British immigrations restrictions and Yitzhak Rabin of pursuing the Oslo Accords while combatting terror: The West has been fighting ISIS even though it helps Assad, on the one hand, and undermining Assad even though it helps ISIS, on the other. The new and possibly more workable sequence is ISIS first, Assad later.

Putin seems to have placed Russia at the head of what could turn out to be an emerging Shi'ite, anti-ISIS coalition that spans from Tehran through Baghdad and Damascus all the way to Beirut. Such a group should dispel anyone’s illusions of a potential Israeli alliance with Moscow, which some Obama-critics have proposed, but probably worries Sunni states in the Middle East much more. Chief among those concerned would be Saudi Arabia, now entangled in escalating tensions with Tehran over the hundreds of Iranian fatalities in the hajj disaster.

These emerging contours of a newly turbulent Middle East present new dangers but also new opportunities for both Obama and Netanyahu; the two may soon find themselves willy-nilly on the same side of the fence in the not-too distant future. That won’t happen, however, if Netanyahu won’t tear out the old pages from his tactical manual, or if he continues to regard Obama as his political rival, if not his sworn enemy.