It has been quite evident to the European leaders that Russia has become increasingly aggressive towards the nations of Eastern Europe. Its actions in the Crimea (occupation and annexation), Eastern Ukraine (support of rebels and deployment of Russian troops), no-notice military exercises, and other threatening activities have many of the European countries deeply concerned. The countries of Poland, Estonia, Latvia, and Lithuania are very anxious to have the support of the North Atlantic Treaty Organization (NATO). These vulnerable nations are very receptive to NATO conducting exercises and permanently stationing military units in their countries to ensure Baltic security.
NATO is in a difficult position. Currently the defense organization does not have the military strength immediately available in the region to defend those four countries and ensure Baltic security. Certainly Poland can withstand a military offensive for some time until NATO comes to its aid; but the three small Baltic nations of Estonia, Latvia, and Lithuania are extremely exposed.
NATO is stationing four battalions in the Baltic region to shore up defenses but it certainly is not enough to fight off a Russian invasion.  At best, the battalions serve as a signal of NATO’s resolve, providing a ‘tripwire’ effect , providing an opportunity to be acquainted with a possible future battlefield, and improving interoperability among NATO countries as a whole. In addition, the four battalions increase Baltic security . . . at least by a small increment.
All three Baltic nations are members of the European Union (EU), the Eurozone (currency), and NATO. As NATO members they participate regularly in NATO training exercises and operations. The three nations have also provided small units and personnel to the NATO mission in Afghanistan; first supporting the International Security Assistance Force (ISAF) until December 2014 and then the Resolute Support Mission (RSM) starting in January 2015. Most of the Baltic units and individuals served in Regional Command North at Mazar-i-Sharif in northern Afghanistan.
The Russians enjoy a number of tactical advantages in a military confrontation with the NATO nations in Eastern Europe – at least in the short-term. The advantages include interior lines, speed of decision making, quantity of readily available forces, and number of tanks in Europe.  These advantages are especially true in considering scenarios involving the Baltic States. Conceivably the Russians could quickly mobilize their substantial military forces in the Russian Federation’s Western Military District to seize all or parts of the Baltic States, ostensibly to protect ethnic Russians.  Part of the logic for the seizure of Crimea and for Russia’s current activities in Eastern Ukraine is the protection of ethnic Russians. The same logic could be applied to the Baltic nations as well.
Is there anything that can be done to shore up the defenses of the Baltic states? There are some who believe steps can be taken to improve Baltic security. A recent RAND Corporation study suggests a “. . . force of seven brigades, including three heavy armored brigades – adequately supported by airpower, land-based fires, and other enablers on the ground and ready to fight at the onset of hostilities – could suffice to prevent the rapid overrun of the Baltic states.” 
Certainly NATO is not standing idly by – it is conducting a series of exercises to prepare its staff and units for a possible confrontation with Russia in Eastern Europe. The NATO Multinational Corps Northeast Headquarters in Szczecin, Poland has doubled its staff and regularly conducts training and command post exercises (CPX). 
The Rand study certainly deserves consideration; however, the possibility of this strong of a response by NATO is not probable. Currently the percentage of Gross Domestic Product (GDP) spent on defense by NATO countries is inadequate; many nations below the desired 2%. In addition, it is highly unlikely that the 28 NATO countries could come to an agreement to support such an expensive and provocative plan of action. There are certainly interesting times ahead – anticipating Russia’s intentions, keeping an eye on Russia’s actions, contemplating NATO’s response, speculating on Baltic security.
 “Four battalions (perhaps 4,000 men) do not come close to deterring the approximately 250,000 troops Russia has in its Western Military District (WMD) bordering NATO”. This quote from NATO Summit Special Series: Estonia and Latvia, Atlantic Council, July 3, 2016.
 The ‘tripwire’ effect is similar to the role that the 2nd Infantry Division plays along the Demilitarized Zone (DMZ) along the northern border of South Korea. If attack by a massive assault by North Korean forces the 2nd ID probably would not stop the invasion but would certainly force the United States to respond militarily. Thus the 2nd ID becomes a deterrent to North Korean aggression.
 See “NATO’s Land Forces: Strength and Speed Matter”, by John W. Nicholson, PRISM 6, No. 2, National Defense University (NDU), page 40.
 See page 42 of Nicholson’s paper where he describes “The Baltic Scenario”.
 See Reinforcing Deterrence on NATO’s Eastern Flank: Wargaming the Defense of the Baltics, by David Shlapak and Michael Johnson, Santa Monica, CA: RAND Corporation, 2016.
 Watch a 4-min long NATO video entitled Multinational Corps Northeast, June 6, 2016.
Map of Baltic Region adapted from CIA map.
Photo of US artillery training in Latvia from NATO video, May 4, 2016.