In this series from the American Statecraft Program, James Goldgeier and Joshua Shifrinson discussed and debated the issues surrounding NATO enlargement in a twenty-first-century exchange of letters. In this final entry, Stephen Wertheim analyzes the contours of their debates. Read all the entries here.

Dear Jim and Josh,

My spy has intercepted your correspondence on horseback!

Thanks to Lin-Manuel Miranda for writing me into the scene. As we wrap up, I’d like to reflect on your exchange—and, by extension, on the wider policy debate, which your letters crystallize.

Stephen Wertheim
Stephen Wertheim is a senior fellow in the American Statecraft Program at the Carnegie Endowment for International Peace.
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I’m struck by how much of your discussion has centered on the effects of NATO enlargement on Russia, namely: to what extent has enlargement caused Russia to turn hostile toward the West and engage in a host of aggressive activities, most recently by invading Ukraine? This is obviously a question of immense importance. It is also difficult to gauge, turning on counterfactual speculation of how Russia would have behaved over three decades if Western leaders had frozen NATO in place after 1990 or perhaps expanded the alliance to a limited number of countries before stopping.

So I suspect that something more fundamental may account for the divergence in your perspectives.

The Nub of the Issue

At root, your disagreement seems to rest on differing assessments of two connected matters:

  1. the seriousness of U.S. interests at play and
  2. the effectiveness of NATO’s deterrent.

It’s these factors, I’d venture, that put the two of you at odds, regardless of how you assess Russia’s intentions.

For Josh, the bottom line is that the Central and East European countries that NATO has admitted since the end of the Cold War have little to do with vital U.S. interests. Safe behind the Atlantic Ocean, and allied with the most wealthy and strategically significant portion of Europe, the United States does not depend on countries east of Germany for its security or prosperity. Therefore the United States should not go to war to defend them—and should not make a political and legal commitment to do so, as NATO membership is widely interpreted to require. As Josh writes, “the United States’ primary interest in Europe over the past century or so has involved preventing the emergence of a European hegemon.” By defending its Cold War allies, the United States prevented Soviet hegemony. After the Cold War, a similar defense perimeter, perhaps slightly expanded to embrace a reunified Germany, would have sufficed to prevent the lesser threat of Russian hegemony.

Josh and Jim probably disagree over whether the United States possesses vital interests in the countries to which NATO has expanded, or, put differently, whether it has such an interest in denying a sphere of influence to Russia. But here the second consideration—the effectiveness of NATO’s deterrent—comes in. Noting that Moscow has never ordered an attack against a member of NATO, Jim contends that bringing a country into the alliance very likely suffices to deter war in the first place. NATO’s Article 5 security commitment is so strong and credible that it virtually guarantees peace and security to the states that join, including, he hopes, to Ukraine in the future. “Only NATO’s Article 5 guarantee can deter Russian aggression against Ukraine over the long term,” Jim writes. Through this argument, Jim seems to suggest that whether the United States should go to war to defend all NATO countries is, in a sense, almost beside the point, because it will probably never need to do so. (Jim allows, however, that stationing some NATO forces in Ukraine may be necessary and notes that NATO allies often request reassurance from Washington in the form of a bolstered military presence.)

Josh’s Base Case Against Enlargement

Josh thinks otherwise. Even after NATO admits a new country, he worries, there remains a nonzero chance that the country could at some point be attacked. Merely joining the alliance is no certain guarantee. Deterrence depends on numerous factors that change over time and across space, including whether the country in question is militarily capable and geographically defensible, whether NATO allies have demonstrated a willingness to fight for the country, and how the would-be attacker gauges its interests and resolve relative to those of its adversaries. In general, the further eastward NATO moves, the less credible its on-paper deterrent becomes—especially if membership were to be extended to Ukraine.

NATO allies, he notes, have declined to fight Russia directly over Ukraine since Russia invaded in 2014 and again in 2022. Even though the alliance’s calculus has been informed by the fact that Ukraine lies outside of NATO, Josh claims that simply admitting Kyiv would not be enough to make NATO’s defense commitment credible. Only a heavy NATO military presence in the country, coupled with a sustained political commitment, might suffice. Josh also worries that the act of bringing Ukraine into NATO could drive Russia to reinvade Ukraine, regardless of the military balance.

Putting the two arguments together, then, Josh’s base case is this: NATO’s enlargement has created unwarranted U.S. defense obligations that might well come due.

From Josh’s standpoint, NATO enlargement since 1990 would still have been a mistake even if Russia had not lashed out in response. It would be bad enough for the United States to face nonzero odds of having to fight a nuclear-armed major power over countries that do not justify that price. An unnecessary U.S.-Russia war could arise from any number of sources—geopolitical rivalry, ethnic tensions, ideological differences—not just from NATO expansion and Russia’s opposition to it. Indeed, even in the heady years of the 1990s, one reason some countries sought to join NATO was the fear that power politics and Russian revanchism could one day return. And return they have.

To the extent that enlarging NATO may have helped to cause Russian aggression, then this becomes all the more reason, from Josh’s perspective, to have confined the alliance to its 1991 perimeter. But even if Josh accepted Jim’s view that Russian aggression has been driven overwhelmingly by internally constituted drives, Josh’s position would remain the same: NATO enlargement was bound to produce a military confrontation with Russia near Russian borders and thus was a strategic error. It would have been better to keep the alliance’s borders in place and wait to see whether Russia would acquire the intentions and capabilities to menace NATO territory.

Jim’s Implicit Criticisms of Enlargement

From today’s vantage point, by contrast, Jim posits that Moscow was highly prone to act imperialistically regardless of Western policy choices. There was almost inevitably going to be a dividing line in Europe, he argues, and the United States was going to be on one side of that line defending its allies against Russia. Wasn’t it better for that line to be located as far eastward as possible?

If one accepts this argument, however, then the way NATO approached enlargement—through a gradual and open-ended process, intended in part to assuage Russian security concerns—seems questionable. In the face of an implacably aggressive Russia, NATO’s best bet might have been to expand as quickly and extensively as practicable, absorbing new members while Russia remained too weak and poor to respond militarily. By this logic, NATO should have taken in all the newcomers it intended to admit in one fell swoop, not on the basis of political criteria but instead on the straightforward grounds of defense against the Russian threat. Nor should NATO have explicitly envisioned successive rounds of enlargement or publicly dangled the prospect of membership to countries such as Georgia and Ukraine, as it did in 2008, without being ready to admit them. Rather than start small and hold out the open door, NATO should have gone big and consolidated its gains.

To be clear, Jim largely approves of how the alliance went about expanding, objecting mainly to NATO’s 2008 declaration that Georgia and Ukraine would one day become members. He believes there was some chance that Russia would democratize, liberalize, and cast off its imperial ambitions. Yet it is worth noting that the more likely Russia was to become aggressive in the decades after the Cold War, the stronger the case becomes for NATO to have enlarged quickly and completely (or not to have enlarged at all). Indeed, if NATO had adopted a high threat perception of Russia from the outset of the post–Cold War period, then the alliance would have altered its very purpose—and forced the United States to confront whether it truly wished to go to war to defend new NATO members. The Senate’s deliberations would have looked different, and potentially the United States might have opted to set limits on NATO’s expansion or urged its European allies to bear a greater defense burden.

The assumption that Russia would turn hostile would have put pressure on the questions with which I began: Do U.S. interests warrant defense commitments all across Europe? And what military measures should the United States and NATO allies take to maintain the credibility of the alliance’s security guarantee?

Perhaps these vital questions loom so large in today’s U.S. politics partly because they were not squarely debated from the beginning. Alas, the hour is late. NATO has much to defend, and there are few countries left to which it could enlarge.

Jim and Josh, thanks for allowing me to examine the contours of your arguments. Greater thanks to both of you for joining this venture. You have proved that it remains possible to conduct a civil conversation about matters of deep disagreement. We need this now more than ever.

Sincerely yours,

Stephen

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