Here’s what the shootdown of Malaysian Airlines Flight 17 means: Russia, with Vladimir Putin at the wheel, just drove off the edge of a cliff.

Now, by this I don’t mean that the United States and the European Union are going to charge in with a new round of sanctions, provide lethal aid to Ukraine, patrol the skies of Ukraine, or anything of that nature. The West didn’t react in time, or with enough resolve, to the initial invasion and partition of Ukraine last spring, and there’s no reason to think our reaction will be any more effective or resolute this time. It would be reassuring to think America and Europe will now fully engage on the problem of Russian aggression, but it’s unlikely.

As far as Russia’s future is concerned, however, it doesn’t matter. The moment Flight 17 exploded was the moment that Putin’s foreign policy officially went over the ledge, and with it his dreams of restored Russian greatness.

Until now, Moscow claimed it was protecting the interests of Russian-speakers in eastern Ukraine. That was nonsense right from the start, but it was nonsense the Americans and Europeans decided they could live with, as galling as it was. (Who, after all, protects the rights of Russians in Russia? Certainly not Putin.) The West looked away as Putin seized Crimea, as we conveniently convinced ourselves that this was some odd ethnic quarrel in which we had no say. Now that a civilian airliner has been blown out of the sky by a Russian missile, however, there can be no further denial that Russia is actively pursuing a major proxy war against its neighbor in the center of Europe, and with a brutality that would make the now-departed marshals of the old Soviet high command smile with approval. This is no longer a war on Ukraine, but a war on the entire post-Cold War international order.

Putin, for his part, has already blamed Ukraine for the loss of the airliner in a careful, weird statement that makes no sense. His complaint, essentially, is that the authorities in Kyiv had the temerity to defend their country against Russia’s invasion and the daily, piecemeal dismantling of the Ukrainian state. With the exception of the usual Kremlin apologists (Professor Stephen Cohen dutifully carried this argument forward the night of the shootdown on Al Jazeera), no one is going to take that position seriously with 300 innocent people strewn all over the fields of eastern Ukraine.

Putin is deflecting blame, of course. He has no choice: he armed, paid, and unleashed a ragtag army of goons in eastern Ukraine, under the command of a Russian intelligence officer who was supposed to provide some adult supervision. Now they’ve betrayed the Kremlin and screwed up.

This leaves Putin with few options. He could admit that the plane was destroyed by the separatists he supports with weapons he provided, and thus confess that Russia itself is complicit in mass murder. Or he can claim that the downing took place without his knowledge or control, which means he will have to cop to providing sophisticated arms to a bunch of bloodthirsty stooges who don’t care who gets hurt. For now, he may have to cut the Russian separatists loose from Moscow, but given Putin’s history, he might also double down and dig in. Either way, the stink of this act will now irrevocably cling to the Russian Federation for as long as Putin is in charge, no matter what his rationalizations.

The Soviet Union – Putin’s first love – likewise never escaped the stain of the downing of a Korean passenger jet in 1983. Just as the Russian separatists are doing now, the Soviets tried to prevent access to the crash area, lied about their own actions, and then blamed others. Although the West imposed some nominal sanctions, the real price was paid in public diplomacy, because the Soviets never recovered an ability to push any further propaganda about their commitment to peace after an act of such savagery. Indeed, when the world erupted in anger, Soviet leader (and former KGB chief) Yuri Andropov was genuinely shocked. Like Putin, he and his comrades lived in a bubble in Moscow, and the public outcry only cemented the Soviet leadership’s paranoid conviction that the world was out to get the USSR. Putin, a typical and mediocre product of Andropov’s KGB, will likely react the same way.

Andropov didn’t have to live with opprobrium for long: he passed away less than six months after the KAL 007 disaster. Putin, however, is a relatively young, healthy man, and he will continue to occupy the world stage as Russia’s supreme ruler. But he will never again be able to portray himself as a savvy, cool broker in international affairs, nor Russia as just another great power. Now, he’s just another Soviet-era thug, a perception that was already growing before the Malaysian airliner plunged out of the sky. No matter how the current crisis ends, Putin’s name will forever be tied to this outrage, and his personal bid to create a more respected Russia through violence and intimidation is permanently defunct.

In the short term, the international community may not manage to muster sanctions against Russia that are any more effective than those imposed on the old USSR. But over the longer term, Putin has done far worse to his own country than any punishment we can levy. He has returned Russia to its cursed role as an international pariah, a country incapable of conducting itself without brutality and conquest. Putin’s Kremlin will likely pay only a modest price for now, but Russia and its people will have to bear the brunt of an increasing and corrosive isolation thrust upon them by their leader and his outdated Soviet fears and insecurities. If the Russian people one day find that NATO has renewed its purpose and that the globalized world community has moved on without them, they will have only Vladimir Putin to blame.

Tom Nichols is Professor of National Security Affairs at the Naval War College and an adjunct at the Harvard Extension School. His most recent book is No Use: Nuclear Weapons and U.S. National Security (University of Pennsylvania, 2014). The views expressed are his own. You can follow him on Twitter: @TheWarRoom_Tom.