There is little doubt that Russia’s annexation of Crimea and other acts of aggression in Ukraine have given birth to a new era of instability in Europe, redrawing borders by force and raising hostility and the possibility of conflict between NATO and Russia. These elements have already been observed in post-World War II history. There was a decreased American military presence on the European continent in the late 1940s, uncertainties about the Soviet Union’s eventual goals, and the very real threat of Soviet military intervention to force nations in the gray zone between the Soviet Union and the West. With the deployment of new SS-20 nuclear missiles in Eastern Europe during the late regime change era in the mid-1970s, Soviet military modernization introduced new uncertainties into the security balance.

Today, Europe faces Russian military modernization as well as Moscow’s readiness to intimidate and meddle in sovereign European nations and countries, threats that the West must address with a decreased US military presence in Europe.

Since 2008, Russia has gained the capacity to swiftly deploy over 100,000 troops on the NATO border with little or no warning to the US and its European allies. At the same time, Russia has suspended its participation in the Conventional Forces in Europe Treaty, removing most of the important provisions that offered transparency and predictability in conventional weaponry.

The West has not kept pace with these developments: NATO has adhered to the 1997 NATO-Russia Founding Act’s that aims to avoiding permanently deploying large combat forces in post-Cold War NATO member nations.

Since the collapse of the Berlin Wall, NATO nations have cut defense budget and focused their reserve forces on expeditionary missions. As a result, there is no substantial NATO military presence east of the Oder/Neisse/Danube Rivers, in area populated by nearly 100 million NATO citizens, to survive an attack by Russia’s more effective armed forces, should one occur.

As a result, there is an obvious and rising conventional imbalance along NATO’s eatery flank, most notably in Poland and the Baltic nations, which border Russian territories. 

According to the Stockholm International Peace Research Institute, NATO nations spent just over $880 billion on defense in 2014, whereas Russia spent just over $91 billion, or approximately 10% of the NATO total.

Russia has claimed that its modernization efforts are aimed at closing the gap between it and NATO; however, Russia’s 2014 military doctrine claims that NATO is beefing up its military forces, citing this as the greatest external military threat to the country. 

But how can there be an imbalance when NATO still spends 10 times as much as Russia and has superior troops in terms of quantity, quality, and capability?

The explanation is that Russia’s quick deployability combined with its expanding conventional weapons weakens NATO’s eastern flank deterrence, which has been the cornerstone of Western strategy since the Cold War.

NATO will retain adequate conventional and nuclear capabilities to persuade any prospective opponent that the dangers of employing force against a NATO ally outweigh the potential benefits to the point that the adversary will prefer peace to war.

The quantity and character of the forces required to deter are determined by the external environment and the adversary’s objectives – the US Army presence in Europe peaked at approximately 300,000 troops during the Cold War, but has since been reduced to around 30,000 for two primary reasons: First, the political developments in Europe that led to the collapse of the Iron Curtain allowed for a time of engagement with Russia, which decreased tensions and reduced the probability of a conflict significantly. Second, in the early post-Cold War period, the US and its Western allies bolstered stability by agreeing with Russia on limitations on conventional military deployments and transparency requirements for conventional force movements.

When combined with Russia’s post-2008 military modernization, the outcome has been a significant improvement in Russia’s capacity to assemble forces and a significant reduction in NATO’s warning time.

NATO presently lacks the capability to repel a potential Russian assault or prevent Russia from seizing territory in the east, particularly along NATO’s eastern borders in Lithuania, Latvia, Estonia, and Poland.

Geographical uncertainty and ambiguity over if and how Russia would use its nuclear weapons add to the security concerns in northeast Europe.

According to public statements by Russian officials and former military commanders, Moscow may see limited nuclear attacks as a means to raise the stakes in a confrontation and “de-escalate” by facing its adversary with the threat of a nuclear retaliation.

Since Russia’s unlawful annexation of Crimea and invasion of eastern Ukraine, the US has made a significant initial response to this aim by rotating US Army forces to NATO’s most vulnerable members: the Baltic nations, Poland, Romania, and Bulgaria. The US should build on its current contribution to security along NATO’s eastern flank by committing to a multi-year forward presence in the east.

Before the conventional imbalance creates instability and heightens threats for NATO and Europe as a whole, the US and its allies must move immediately to begin redressing it.