Do Russia's war games have a darker purpose?
JUDY WOODRUFF: This week, Russia has been conducting a large-scale military exercise within the territory of one of its neighbors, Belarus, a former Soviet republic.
Russian units are also war-gaming near the borders of three Baltic NATO member states which were also once part of the Soviet Union.
Moscow says that this is a defensive exercise, but others see a more ominous purpose.
Nick Schifrin has our report.
NICK SCHIFRIN: On day two of the imagined war between NATO and Russia, the cacophony of combat crescendoed.
Russia's military exercise is called Zapad, or West, and it began with the military responding to a hypothetical threat to Russian ally Belarus. Soldiers quickly crossed the Belarus border and unleashed hell; 70 jets and helicopters, 250 tanks helped defend Belarus. And that was before the scenario escalated.
An airborne operation dropped tanks 20 miles from NATO member Estonia's border, preventing a hypothetical incursion by NATO troops. Ten Russian ships set to sea to escape hypothetical incoming NATO cruise missile strikes.
And witnessing it all, Russian commander in chief and President Vladimir Putin, whose allies say they genuinely fear NATO launching this kind of war.
ANDREI TSYGANKOV, San Francisco State University: NATO now is after Russia's regime change, and, therefore, we have to defend ourselves. So it is a defensive exercise. But really it is not just really about military deterrence. It's about political survival as well.
NICK SCHIFRIN: Andrei Tsygankov is a Russian politics professor at San Francisco State University. He echoes the Russian establishment when he says NATO's support of revolutions in previously Soviet states and satellites and NATO's expansion to Russia's borders convince Russia NATO's an existential threat, and Zapad provides necessary deterrence.
ANDREI TSYGANKOV: NATO is not merely a military alliance. It's a civilizational clash. And NATO is the military outpost of the Western civilization, and, therefore, it's just a tool to ultimately change regimes around Russia.
NICK SCHIFRIN: But, for the West, Russia is the threat. Since the 2014 Crimea annexation, the U.S. has painted Russia as a danger to international order. Earlier this year, the U.S. called the Zapad exercise a Trojan horse, whose real aim was leaving troops in Belarus or invading a NATO ally.
LT. GEN. BEN HODGES, Commander, U.S. Army Europe: When they went into Crimea, that was against the backdrop of an exercise. When they went to Georgia, it was an exercise.
NICK SCHIFRIN: General Ben Hodges commands the U.S. Army in Europe. He spoke in June at a U.S.-Poland exercise designed to deter Russia from crossing any more borders.
LT. GEN. BEN HODGES: They don't have a reputation for being trustworthy when it comes to compliance. We have to practice. We have to demonstrate that we can support allies.
NICK SCHIFRIN: Lithuania was so concerned about the Zapad exercises, it installed a new fence on its Russian border to deter what Defense Minister Raimundas Karoblis called Russian dreams of supremacy.
RAIMUNDAS KAROBLIS, Defense Minister, Lithuania: It's clear Russia really wants to establish its domination and change the defense in all Europe.
NICK SCHIFRIN: Those fears are understandable, but there is a larger, more ominous threat argues National Defense University fellow Peter Zwack.
PETER ZWACK, National Defense University: It is the more visible muscular arm of a Russian military, but it's not just the military. It's almost societal.
NICK SCHIFRIN: Zwack is a retired U.S. brigadier general and a former U.S. defense attache to Moscow. He says the real threat posed by Russia isn't leaving troops in Belarus or invading a NATO member, but a newly defined Russian strategy that combines conventional forces with asymmetric forms of warfare, annexing Crimea, supporting separatists who destabilize Eastern Ukraine, and hacking the 2016 U.S. election.
PETER ZWACK: For the Russians, yes, asymmetry, you go after somebody's strengths, but you do it also in recognition of your own weaknesses.
And Russia knows it has weaknesses. If the West and allies worldwide were to pull together, the Russians would be outmanned, outgunned.
NICK SCHIFRIN: Zapad is designed to close that gap. It's also designed to soften NATO resolve, something all militaries do.
Last year, I attended NATO exercises 30 miles from the Russian border. American soldiers practiced waging war against a military with equal firepower. On the training ground, there was even a burned-out Soviet-style tank for target practice, which means both sides will continue to exercise, and both sides will continue using their militaries as a means to ensure peace.
PETER ZWACK: NATO today, in this really, difficult chaotic world, I believe, is the core alliance of our civilization. I believe it also needs to find a way, the Russians need to find a way, both, to coexist.
NICK SCHIFRIN: And that would allow all these preparations for war to remain exercises.
For the PBS NewsHour, I'm Nick Schifrin.