As the West searches for an adequate policy response to Russian President Vladimir Putin’s ongoing aggression in Ukraine, American and European policymakers would do well to reread George F. Kennan’s famous “X” article, published in the July 1947 issue of Foreign Affairs. Compelling then, Kennan’s case for containing Russia makes just as much sense now.

Kennan’s central claim was that “the political personality of Soviet power as we know it today is the product of ideology and circumstances.” On the one hand, there was messianic Marxism, which rested on a Manichean view of the world and promised victory over capitalism to the socialist proletariat. On the other hand, there was a genuine belief that the rest of the world was hostile—antagonism that justified Russia’s pursuit of absolute power at home.

The policy consequences of “ideology and circumstances” were twofold. First, Soviet Russia would have to expand, as its ideology dictated. But, second, it was under no compulsion to expand immediately and unconditionally. Quite the contrary, Kennan emphasized. He wrote, “Its political action is a fluid stream which moves constantly, wherever it is permitted to move, toward a given goal. Its main concern is to make sure that it has filled every nook and cranny available to it in the basin of world power. But if it finds unassailable barriers in its path, it accepts these philosophically and accommodates itself to them.”

In his article, Kennan drew the logical consequences of Soviet behavior for the West. For one thing, Western policies should be “no less steady in their purpose, and no less variegated and resourceful in their application, than those of the Soviet Union itself.” In particular, “the Soviet pressure against the free institutions of the Western world is something that can be contained by the adroit and vigilant application of counterforce at a series of constantly shifting geographical and political points, corresponding to the shifts and maneuvers of Soviet policy, but which cannot be charmed or talked out of existence.”

Indeed, containment, Kennan emphasized, was not only about “counterforce.” What we would today call soft power also mattered: the United States, he wrote, should “create among the peoples of the world generally the impression of a country which knows what it wants, which is coping successfully with the problems of its internal life and with the responsibilities of a world power, and which has a spiritual vitality capable of holding its own among the major ideological currents of the time.”

Ultimately, Kennan concluded, a combination of internal Soviet weaknesses and containment would “promote tendencies which must eventually find their outlet in either the breakup or the gradual mellowing of Soviet power. For no mystical, messianic movement—and particularly not that of the Kremlin—can face frustration indefinitely without eventually adjusting itself in one way or another to the logic of that state of affairs.”

Although Kennan’s article puported to address the sources of Soviet conduct, it’s clear from the text that he equated the Soviet Union with Russia, Soviet leaders with Russian leaders, and Soviet conduct with Russian conduct. And that is why, unsurprisingly perhaps, his analysis holds up remarkably well when applied to Putin’s Russia.

To be sure, the ideology is different today. No one in Putin’s regime believes in Marxism. But the superiority of Russia and Russian civilization are still closely held values, as is the belief that the West is hostile and that the country needs a strong leader, Putin, to assert Russia’s greatness and combat Western influence.

The quest for absolute power at home is also familiar. Ever since he first appeared on the Russian political stage in 1999, Putin has been assiduously constructing a highly centralized authoritarian regime with himself at the center. Putin’s cult of personality emphasizes his hyper-masculinity and his control over a worshipful public. Putin’s is no longer a simple authoritarian regime run by a non-charismatic ruler with little sex appeal and no overarching ideology. In its structure and, increasingly, tone, Russia’s current regime resembles those of the fascists of yore.

Like the Soviet Union, Putin’s Russia fosters antagonism to the West, and, like the Soviet Union, it feels impelled to expand, but not “immediately and unconditionally” or against “unassailable barriers.” It is under no real threat: NATO has been in decline, Europe has been cutting its defense budget, and the United States has been distracted by the Middle East and domestic priorities. Instead, Putin’s neoimperial ideology and his standing as Russia’s all-powerful leader require him to gather former imperial territories.

The implications for the West of Kennan’s analysis are no less relevant today. For starters, the United States and Europe must understand that “there can never be on Moscow’s side any sincere assumption of a community of aims between the Soviet Union and powers which are regarded as capitalist.” Second, Putin’s Russia “can be effectively countered not by sporadic acts which represent the momentary whims of democratic opinion but only by intelligent long-range policies on the part of Russia's adversaries.” It’s high time, in other words, for the West to abandon its illusions about Putin and his regime and develop a serious, steady, long-term policy response to Russian expansionism.

And that, of course, means containment. In today’s terms, the front lines of containment are the non-Russian states in the potential path of Russian expansion. Seen in this light, a divided Ukraine occupies the same role in today’s containment strategy as a divided Germany did in yesterday’s. Ukraine should therefore be the recipient of similar financial, political, and military assistance. Finland, Sweden, Estonia, Latvia, Lithuania, and Moldova—as well as, possibly, Belarus and Kazakhstan—must also figure as points where counterforce, in the form of enhanced military assistance, will have to be applied. The goal in all these cases is not to roll back Russian power but to stop its penetration of the non-Russian post-Soviet states.

Central to today’s containment policy is constraining Russia’s ability to use energy as a weapon. Halting the building of the South Stream pipeline, reducing Europe’s dependence on Russian oil and gas, and helping Ukraine reform its energy sector will be key. Last but not least, sanctions—as forms of minimizing Russia’s economic power—must be maintained and possibly intensified.

The United States and Europe must also work on their soft-power appeal. If they claim to stand for democracy, human rights, and “European values,” then they should actively promote them—especially in those places into which Russia seeks to expand. It is there that Western values can be made to mean something essential to their very existence—or, if inconsistently applied, can be revealed to be utterly hollow.

Last but not least, the West should always be ready to provide Putin with a face-saving exit from his aggressive behavior: “it is a sine qua non of successful dealing with Russia,” Kennan wrote, “that the foreign government in question should remain at all times cool and collected and that its demands on Russian policy should be put forward in such a manner as to leave the way open for a compliance not too detrimental to Russian prestige.” In sum, counterforce plus soft power plus a willingness to compromise make for the best form of containment, whether in 1947 or in 2014.

The West’s face-saving measures could range from welcoming Putin as an equal interlocutor in international negotiations to seeking Russian cooperation in conflicts such as the one in Iraq and Syria to agreeing to possible limits on NATO enlargement. Naturally, the West could harbor no illusions about “any sincere assumption of a community of aims” and would have to insist on verifiable quid pro quos in return for its olive branches. That may be a challenge. In light of Putin’s violation of the 1994 Budapest Memorandum on Security Assurances, his contradictory explanations of the annexation of Crimea, and his continued denial of a Russian troop presence in eastern Ukraine, the West will have to insist that only measurable changes in behavior will warrant Western consideration of Russia’s desires.

Kennan’s optimism about the future can also be applied today. Thanks to Western sanctions and the general Russian economic stagnation, Putin’s Russia is rapidly approaching irreparable decay. The fascistic regime Putin built suffers from the pathologies of all such states: vast corruption, overcentralization, inefficiency, ineffectiveness, and bureaucratic empire-building. With containment, such decline—or, as Kennan suggested, genuine reform—could be accelerated.

Putin’s inevitably waning cult (after all, aging leaders cannot sustain hyper-masculine charisma) will set in motion, as Kennan also predicted, a power struggle: “It is always possible that another transfer of preeminent power may take place quietly and inconspicuously, with no repercussions anywhere. But again, it is possible that the questions involved may … shake Soviet power to its foundations.” A wise, sustained, steady policy of containment redux could ensure that, when Putin’s regime is shaken to its foundations, the outcome will be favorable for Russians, their aggrieved neighbors, and the world.