The iconic words of the North Atlantic Treaty, the real teeth in the West's bedrock military alliance throughout the Cold War, begin in the document's Article 5: "The Parties agree that an armed attack against one or more of them in Europe or North America shall be considered an attack against them all." Since 1949, that single article has carried the gargantuan burden of guaranteeing the security of the Western world. The actual strength of this particular article, however, is often overestimated and perceived as resulting in an automated military response to any attack on members of NATO. Article 5 has several built-in weaknesses that stem from both the consensus voting procedure required to invoke the article and the vague language in the continuation of the article itself: "if such an armed attack occurs, each of them […] will assist the Party or Parties so attacked by taking forthwith, individually and in concert with the other Parties, such action as it deems necessary, including the use of armed force, to restore and maintain the security of the North Atlantic area." Thus, it raises the question of whether NATO is in fact a valid political tool for military deterrence, or whether the treaty is simply an empty statement of intent.
Why ponder this question? Given the state of relations between the Russian Federation and members of NATO and the return of threatening military maneuvers on both sides of their borders, the issue of deterrence is center stage again. The Russian annexation of Crimea and Russia's military actions in eastern Ukraine, which forced a paradigm shift away from the notion that the age of expansionism was in Europe's past, have renewed the relevance of the North Atlantic Treaty. Along with the return of the relevance of the North Atlantic Treaty, however, comes the return of the question that has plagued its existence since the beginning: If NATO is challenged, will the treaty remain intact and result in a concerted military response as intended?
Perhaps this question is already going too far, since NATO's original and foremost intent is not necessarily to mount that military response but to use the potential of military action to deter any other powers from attacking its members in the first place. The treaty is thus one of many balance-of-power structures that have been established in attempts to prevent the outbreak of war throughout the course of history.
The concept of balance of power has been a dominant mechanism in international security since the 1648 Peace of Westphalia introduced the idea of co-existing sovereign states. In its most basic form, balance-of-power theory assumes security emerges from a situation in which no single power is strong enough to challenge all others, assuming weaker powers will form alliances to balance against stronger powers. Article 5 of the North Atlantic Treaty introduces exactly that element through the concept of collective self-defense. The alliance was established on the need of weaker European states to pool their military capabilities with the United States in order to ward off invasion by the Soviet Union while, from a U.S. perspective, denying Western Europe to the Soviets by tying the countries there into an alliance structure.
The Downside of an Alliance
One of the major pitfalls of alliance structures in such a balance-of-power mechanism is the actual strength of the alliance. Alliances are built on a convergence of the interests of a group of states at a certain point in time, but these individual interests do not necessarily continue to travel in the same direction from that point on. Treaties are but treaties — they remain just words on paper, and while they are not necessarily insignificant in international relations, it is key to realize that each and every state constantly re-evaluates its own interests and actions based on its capabilities, constraints and interests at that moment. All too often, these interests no longer align with treaties signed in the past. This is perhaps best described by the adage that has been pounded into the minds of all those who study international relations, as stated by Lord Palmerston in his speech to the House of Commons in 1848: "We have no eternal allies, and we have no perpetual enemies. Our interests are eternal and perpetual, and those interests it is our duty to follow." Although Lord Palmerston's quote relates to so much more than simply the value of treaties, it applies perfectly here. Look back in time, for example, at the Treaty of Non-aggression between Germany and the Soviet Union in 1939. While this treaty served both parties' interests at the time of signing, it fell apart less than two years later, when German forces invaded the Soviet Union.
The North Atlantic Treaty is no exception here, and while the treaty implies a certain reaction from its signatories in case of an attack, such an attack will prompt a decision-making process in each of these signatories during which adhering to the treaty by invoking Article 5 will be but one option. This is where thinking of the practical implementation of the treaty becomes an important aspect of gauging its utility. The treaty does not specify what constitutes an "attack;" this is decided through a vote by the permanent representation of each member state to the North Atlantic Council, and any decision in the council has to be based on a unanimous vote. The requirement for this type of consensus voting of course was not introduced to make Article 5 a lame duck. It safeguards the national sovereignty of the NATO member states by not drawing them into armed conflict against their will. Without the ability to maintain control over the initiation of military action, the risks entailed in the treaty would have easily outweighed the benefit of the alliance. However, the price paid to achieve this compromise is the potential for political indecisiveness paralyzing the alliance in case of an actual confrontation.
This is an issue of notable concern in the current NATO alliance, expanded after the Cold War to include several Eastern European members. The interests and capabilities of signatories to the treaty diverge substantially and no longer guarantee a monolithic interest in confronting any attack on member states. NATO member states in Western Europe perceive a threat from Russia very differently from those Eastern European states located close to Russia. Would Portugal, for example, be willing to go to war with Russia to prevent Russia's seizure of a corner of Estonia?
At the same time, there is also a divergence between members of the alliance that have significant military capabilities and are thus "security providers" rather than "security consumers." These significant differences in member states' positions result in entirely different calculations about when getting drawn into a conflict is necessary. Even if all members come together and invoke Article 5, the article itself still merely states that they "will assist the Party or Parties so attacked by taking forthwith, individually and in concert with the other Parties, such action as it deems necessary." The large differences in perception of threat, and especially the military capabilities of member states, would have a tremendous effect on what it "deems necessary." This point is perhaps most clearly illustrated by the decision to invoke Article 5 in 2001, in response to the 9/11 terrorist attacks against the United States. This initially led to military action by only the United States and a coalition of close allies; NATO became involved as an organization only in 2003. While eventually all signatories to the treaty took part in the operation, the scale and scope of their involvement was still very much subject to their own national interests.
The Alliance's Military Framework
NATO is, of course, more than just a treaty. That is to say, it is more than just a document prescribing the potential retaliation to an attack. The treaty has, in a sense, materialized along a two-pronged approach: One is the political deterrent that Article 5 represents, and the other is the establishment of a significant military framework. As per the ancient Latin proverb "Si vis pacem para bellum" ("If you want peace, prepare for war"), NATO has built an incredible capability that its member states share through the use of common standards and procedures. This interoperability theoretically lifts the total capabilities of the alliance's armed forces to a level higher than simply the sum of its members' armed forces. Thus, a potential attacker would be deterred not only by the potential for Article 5 to be invoked, but also by the military power the alliance, or parts thereof, could muster against it. Importantly, it allows the United States to project power quite efficiently across the Atlantic Ocean into Europe.
This framework does not only lend itself to NATO as a whole, however; member states conducting joint operations not under the NATO aegis have relied upon this interoperability before. This leads to what can be seen as both a solution to those gaps left by the North Atlantic Treaty and a useful consequence of the alliance structure. As interests diverge within NATO as a whole, they tend to align among certain members within the alliance. The United States, for example, has taken much more of an interest in the Eastern European member states' perceived security threat from Russia than Western European member states have. Operation Atlantic Resolve, which the United States is conducting on its own behalf, uses a significant amount of know-how and depends on procedures and standards implemented by the alliance as it maintains a perpetual rotation of U.S. forces through Eastern Europe from one military exercise to the next. It could be considered that NATO makes up for its shortcomings by facilitating parallel security commitments based on real converging interests between member states.
Gauging Article 5's Success
Perhaps the most difficult question to respond to is whether, regardless of its exact procedural implications and expectations of its success, Article 5 has been successful so far. Since its establishment, no NATO member state has been invaded by a foreign military power. Although Article 5 was invoked following the 9/11 attacks, the terrorist threat arguably posed a different kind of risk than the conventional threat signatories had in mind when the treaty was compiled. In true chicken-or-egg fashion, it is impossible to determine whether NATO members were never invaded because of the deterrent imposed by Article 5, or whether Article 5 has not been invoked as a self-defense measure because nobody has had the intent to attack NATO. This ambiguity could prove to be a challenge to NATO in the future; potential indecisiveness could be a significant factor in inviting aggression from across its borders.
Throughout the Ukraine crisis, the idea of Russia applying "Hybrid Warfare" to the Baltics has been floated often, and the exact response by the individual members of the alliance would be difficult to predict in such a case. Even if Russia were to overtly invade the Baltics, perhaps intending to disintegrate NATO's deterrent by openly and unambiguously challenging Article 5 in some sort of a "Bluff Krieg," the freedom of the Baltic States may not weigh up against the prospect of initiating the third world war for many of the alliance's members. In the end, the response to such attacks, regardless of their shape or form and regardless of what the North Atlantic Treaty commands, will come down to each member state's cost-benefit analysis.