This spring Russia has massed 80,000 troops and thousands of vehicles near Ukraine.

Now NATO is mobilizing 28,000 of its own troops for a sprawling, months-long series of war games with its location – you guessed it – near Ukraine.

While the alliance’s Defender Europe 21 exercise is just the latest iteration of an annual training event and has been in the works for a long time, its geography is no accident.

NATO, and the United States in particular, are determined to match Russian deployments where Russia is most aggressive.

“Exercise Defender Europe will end in June,” Pentagon spokesman John Kirby said, “but not before demonstrating the readiness, lethality and interoperability of joint forces, reinforcing the commitment of the United States to our allies and partners and providing an exceptional opportunity to highlight the great work that our men and women do every day and in the region, the Balkan and Black Sea regions in particular, and throughout Europe and the African area of ​​operations. “

The Russian build-up is the latest in an ebb and flow of forces following Moscow’s 2014 invasion of the Crimean Peninsula and the related – and ongoing – Russian-backed insurgency in eastern Ukraine .

In recent times, Moscow has been trying to find a corner on a particular problem: water. Ukraine largely controls the flow of fresh water to Crimea, which after seven years of Russian control is turning into a major military outpost.

While Ukraine has increased its military spending in recent years, it remains low compared to Russia. And anxious to provoke the Kremlin, NATO did not extend an invitation to Kiev to join the alliance. Instead, Ukraine, like Georgia, another former Soviet republic, is simply a NATO partner.

As a partner, Ukraine sends observers to some NATO exercises, including Defender Europe 21. The exercise involves troops or observers from 26 countries.

No treaty guarantees that the Atlantic alliance would mobilize to defend Ukraine against direct attack. But it’s a safe bet that a Russian attack anywhere along NATO’s eastern flank would provoke a powerful NATO response.

NATO, however, is weakest in the east, where member states, including some ex-Soviets, are small and relatively poor. Estonia, Latvia and Lithuania in the Baltic region. Bulgaria, Hungary and Romania and others in the Balkans and around the Black Sea.

If war breaks out near Ukraine, NATO would have to project forces from west to east. The heaviest reinforcements could come from the United States, which is why the early phases of Defender Europe 21 are mainly logistics exercises.

The first phase began in March, when the US Transportation Command dispatched thousands of vehicles and tonnes of supplies from the United States to ports across Europe including Albania, Croatia, Greece and Slovenia on along NATO’s southern flank.

Perhaps most impressive, the US Military Sealift Command activated cargo ships, including the 950-foot vehicle carrier. Bob Hope to transport the United States Army 53rd Infantry Brigade Combat Team based in Florida from Jacksonville to the Port of Durres in Albania.

In Durrès, Bob HopeArmy crew and transport troops simulated the unloading under war conditions. Imagining that enemy attacks had damaged port facilities, the Americans built a temporary floating jetty and transferred vehicles from Bob Hope army landing craft and other ships, which carried them ashore.

“A secure port is never guaranteed, so crews must practice an alternative method of unloading,” said US Navy captain James Hilton, a Pentagon representative in Albania.

Once the equipment is ashore, soldiers from Florida will stumble upon it and disperse into southern and eastern Europe, where they will meet troops from other NATO nations for shooting war games. real and other workouts.

In June, the deployment process will be reversed. The ships will load and return to the United States. And, NATO leaders surely hope, the alliance will have made a clear statement. It can move forces over great distances and concentrate them wherever Russia is massing its own forces.