A Romanian special forces member disembarks from a helicopter.
A Romanian special forces member disembarks from a helicopter to the U.S. Navy guided-missile destroyer USS Truxtun during a NATO military drill in the Black Sea, March 19, 2014.
Stoyan Nenov / Courtesy Reuters

On April 16, NATO Secretary General Anders Fogh Rasmussen announced that NATO would be stepping up its air patrols near the Baltic States and conducting some additional ship maneuvers and deployments of military trainers in the area. The decision to do so was wise; the increased NATO presence will aid in reconnaissance and help reassure frontline NATO states, which undoubtedly feel threatened by Russian President Vladimir Putin's recent adventures in Ukraine. The deployments are also a reasonable and proportionate response to Russia's own recent buzzing of a U.S. ship in the Black Sea.

NATO’s moves in the Baltics, however, do not solve the problem of how the organization should respond if Russia does, indeed, move into eastern Ukraine. Although that might once have been unthinkable, Putin has done many unthinkable things in recent months. So it is worth planning for it now.

Should Russia march into eastern Ukraine, the best way to respond would be to set up a permanent brigade of American light forces in the most acutely exposed NATO member countries, namely, the Baltics: Estonia, Latvia, and Lithuania.

Such a brigade, plus support, could include anywhere between 3,000 and 7,000 troops, a large enough number to guarantee that the force would have significant forward capabilities. Roughly one battalion of soldiers, or some 1,000 G.I.s, would be stationed in each of two Baltic States. The remainder of the brigade -- and the brigade headquarters -- would settle in the third.

Together, these troops would conduct routine and ongoing training of Baltic militaries and also help patrol NATO’s eastern frontier, creating a trip wire along the border with Russia. The patrols would also allow Washington and Brussels to confirm to Moscow and the world that any Russian minorities in the region are being protected and accorded their full rights as citizens, lest the Kremlin try to argue otherwise as a pretext for further aggression.

The purpose of the brigade would not be to threaten Russia -- Washington and Brussels couldn’t announce their plans with any bravado or defiance. Rather, it would be to deter Russia from attacking a NATO member, supposedly to protect Russians and Russian speakers. The brigade’s very size -- quite modest by the standards of great powers in the region -- would limit its offensive capabilities. So would its dearth of armaments; the United States and NATO would hold off on deploying any offensive airpower beyond attack helicopters, which are a normal part of permanent bases. The 10th Mountain Division from Fort Drum, New York, would be ideally suited for the job because it is a light force accustomed to cold-weather conditions; alternatively, the United States could contribute a Stryker brigade, which is usually deployed with light- to medium-weight vehicles.

Ideally, the United States would not be alone in this mission. One or two other NATO countries could each send a comparable number of forces to a Baltic country. France, for example, could send 1,000 troops to Lithuania. The Low Countries could drum up another 1,000 to send to Estonia. And some combination of other NATO allies could pull together a final 1,000 to station in Latvia.

It is, of course, hard to imagine that Russia would threaten the Baltics (or Poland) even in the absence of such a deployment. Then again, few expected any of what happened this year in Ukraine. Further Russian aggression is far from a foregone conclusion, and NATO and others should continue to try to deter it by signaling a willingness to tighten the economic screws. If it happens, though, it would be a radical provocation that would force NATO to start thinking in ways it had not before.

In 1997, NATO pledged to Moscow that it would not base combat units forward on the territories of new member states. But Russia has done a number of things that weren’t considered plausible when that pledge was made 17 years ago. Indeed, in terms of international commitments and obligations, the bigger issue is that Russia has made a mockery of NATO's and its own 1994 pledge to vouch for Ukraine's security. At this point, NATO cannot afford to allow Putin to harbor any doubts about its other commitments to its allies. By basing troops in the Baltics, it can show its strength in a way that doesn’t provoke a major war over a non-NATO member.

There will be those in the United States who will argue against yet another American military deployment at a time when the United States is economically strapped and militarily overextended. But stationing permanent forces in the Baltics need not be a major burden. Because of the small size of the deployment, for example, it would not threaten the Obama administration’s rebalance to Asia. To be sure, there would be additional one-time costs associated with building new and durable bases in the Baltics. A reasonable proxy for the expenses might be the sum associated with moving a comparable number of U.S. marines from Okinawa to new facilities in Guam in coming years, which is estimated to be in the range of $10 billion. There may be less expensive ways to manage in the Baltics. But even a $5 billion cost, spread over five years, would be modest by Pentagon standards, especially considering that the stakes -- stability in Europe -- are so high.

Moreover, with most U.S. army forces already coming home, first from Iraq and now Afghanistan, the new mission would hardly put a strain on a U.S. military service accustomed to sustaining 10 to 20 brigades abroad over the last dozen years. And there is little reason to think that,  once new facilities are constructed, deployment in the Baltics would be any more onerous for American personnel than going to Germany, Italy, or the United Kingdom.

It is still worth hoping that it doesn’t come to this. But if it does, the United States and NATO will have a straightforward, proportionate, and effective military response ready and waiting.

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  • MICHAEL O'HANLON is Senior Fellow with the Center for 21st Century Security and Intelligence and director of research for the Foreign Policy program at the Brookings Institution, He is co-author, with Jim Steinberg, of Strategic Reassurance and Resolve: U.S.-China Relations in the 21st Century.
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