History and culture March 12, 2022 Updated: September 17, 2026 23 min read THY-REALITY

NATO: Defensive Alliance, Geopolitical Power, and the Limits of Collective Security

NATO began as collective defence against the Soviet threat, but after the Cold War it enlarged, intervened beyond member territory, and became a wider Western security infrastructure. This critical audit examines enlargement, Kosovo, Afghanistan, Libya, Gladio, Ukraine, U.S. weight, and the defence industry.

NATO can be described by two very different sentences that are both partly true: it is a treaty-based defensive alliance whose core is the collective defence of its members, and it is also the most powerful permanent military-political infrastructure of the West. If we choose only the first sentence, we miss Kosovo, Afghanistan, Libya, enlargement, and global partnerships. If we choose only the second, we miss voluntary membership, consensus decision-making, and the very real security interests of states that sought admission.

The useful question is therefore not whether NATO is simply “good” or “bad.” It is more useful to ask what it promised, what it actually did, who gained security, who perceived greater threat, and where defensive purposes became intertwined with power projection. That requires placing the Alliance’s official account beside archival documents, international law, parliamentary investigations, arms data, and critical scholarship.

After the Cold War, NATO expanded from 16 to 32 members, conducted operations far beyond the classic geography of North Atlantic territorial defence, and in its 2022 Strategic Concept listed crisis prevention and management and cooperative security alongside deterrence and defence as core tasks. At the same time, Article 5 has been formally invoked only once in more than seven decades — after the attacks of 11 September 2001.

This article therefore tests the strongest claims on both sides: that NATO is merely defensive; that it is simply an extension of the U.S. military; that post-1990 enlargement was only an innocent process of voluntary choice; that it was a betrayal of Western assurances; that interventions protected civilians; and that they primarily served geopolitical power. In each case, it separates the documented core from the interpretation that requires an additional causal step.

What the treaty actually says: collective defence, but not automatic war

The North Atlantic Treaty was signed in 1949 in the early Cold War. Article 5 states that an armed attack on one member will be considered an attack on all, but it leaves each Ally to take “such action as it deems necessary,” including the use of armed force. It is therefore not an automatic mechanism in which every attack triggers the same military response by every state without further political choice.

The institutional structure also matters. NATO does not decide by majority vote: decisions are taken by consensus. Formally, even a small Ally can block a common decision. This corrects the simplified image of Washington simply ordering the Alliance to act. Yet formal equality is not material equality: the United States provides the largest military share, nuclear deterrence, major strategic enablers, and a large part of the command infrastructure.

Article 5 has been formally invoked only once, after 9/11. That confirms that collective defence is a real core commitment, but it does not explain most post-Cold War NATO operations. To understand the Alliance, one must also examine crisis management, operations beyond member territory, and the expansion of its political-military space.

President Harry S. Truman signing the document implementing the North Atlantic Treaty in August 1949. — **The alliance’s institutional beginning.** President Harry S. Truman signs the document implementing the North Atlantic Treaty on 24 August 1949. The photograph helps distinguish the original treaty framework from the later expansion of NATO missions and operations. Image: Abbie Rowe / U.S. National Archives via Wikimedia Commons Public domain — U.S. federal government work

After the Cold War: why did the Alliance not end with the Warsaw Pact?

NATO’s original strategic rationale was Soviet pressure in Europe. After the Soviet Union collapsed in 1991, it was reasonable to ask whether the Alliance had lost its purpose. Rather than dissolve, NATO adapted: alongside collective defence it increasingly assumed stabilisation, crisis-management, and partnership functions. The Balkans became the first major arena of that transformation, followed by Afghanistan after 2001.

Supporters of this transformation stress that Central and Eastern European states themselves sought membership, often because of their historical experience of Soviet domination and uncertainty about Russia’s future. Academic research also finds effects on civilian control of armed forces, defence reform, and institutional consolidation among candidates. NATO did not simply “occupy” Eastern Europe; many states actively sought to join.

The critical problem lies elsewhere: security gained by one side can be perceived as a threat by another. Enlarging a military alliance changes strategic geography even when new members enter voluntarily. This is the classic security dilemma: what one side sees as defensive reassurance, another may see as opposing military infrastructure moving closer. That does not make Russia’s interpretation automatically correct or diminish smaller states’ right to choose; it is simply a real mechanism in post-1990 European security.

“Not one inch eastward”: promise, proposal, or lost political option?

Archival records confirm that U.S. Secretary of State James Baker used language in February 1990 discussions with Mikhail Gorbachev suggesting that NATO jurisdiction or military presence would move “not one inch eastward.” Similar reassurances appeared in West German discussions. The claim that non-expansion was never mentioned at all is therefore inconsistent with the documentary record.

The second half of the story matters just as much. No general prohibition on future NATO enlargement was written into the German reunification settlement or a later binding agreement with Russia. Historians therefore disagree about the scope and status of the assurances. Joshua Shifrinson argues from archival evidence that Soviet leaders received substantial informal assurances about NATO’s future restraint; other scholars emphasise that the idea was short-lived and primarily connected to the military status of former East Germany.

The most careful conclusion is two-part: there was no legally binding agreement permanently forbidding the admission of Eastern European states; documented political assurances nevertheless created different Soviet expectations about the post-Cold War security order. The dispute is therefore more than mere propaganda, but less than a simple story of a violated written treaty.

Enlargement: voluntary accession and a simultaneous shift in Europe’s balance

NATO admitted Poland, the Czech Republic, and Hungary in 1999, seven more states in 2004 — including Slovenia and the three Baltic republics — and reached 32 members by 2024. Accession requires an applicant’s desire to join and consensus among existing members, so it is inaccurate to describe enlargement as forced incorporation of states that opposed membership.

Yet critics warned about enlargement long before Vladimir Putin. Richard Haass argued in 1997 that expansion could alienate Russia, raise costs, and reduce the security of states left outside; George Kennan called it a major strategic error. Supporters, by contrast, argued that membership reduced uncertainty, discouraged interstate disputes, and strengthened democratic civilian control over armed forces.

The 1997 NATO-Russia Founding Act attempted to combine two tracks: continued enlargement and institutional cooperation with Moscow. NATO stated that it had no intention, plan, or reason to deploy nuclear weapons on new members’ territory and, in the security conditions of the time, did not envisage additional permanent stationing of substantial combat forces. This shows that Western leaders recognised Russian security concerns — but chose to manage them rather than abandon enlargement.

Kosovo 1999: humanitarian argument, legal gap, and the cost of bombing

Operation Allied Force against the Federal Republic of Yugoslavia marked the sharpest break with the image of NATO as an alliance that only defended member territory. NATO justified the campaign by the humanitarian catastrophe in Kosovo and the failure of diplomacy. The UN Security Council, however, did not adopt a resolution explicitly authorising the use of force, leaving the legal basis contested.

The Independent International Commission on Kosovo later used the well-known formulation that the intervention was illegal but legitimate — illegal because it lacked Security Council authorisation, legitimate in its view because of the humanitarian purpose. International-law scholars such as Bruno Simma also highlighted the breach with the strict UN Charter framework. The case exposes a genuine tension between moral claims and legal authority.

The criticism is not only abstractly legal. Human Rights Watch estimated that around 500 Yugoslav civilians were killed in roughly 90 incidents during the 78-day campaign and found that some targets were unlawful or attacks insufficiently precautionary. At the same time, it also documented mass abuses and persecution of Kosovo Albanians by Yugoslav and Serbian forces. A serious audit does not erase one set of victims in order to recognise the other.

Afghanistan: the only Article 5 invocation and twenty years of expanding objectives

After 9/11, NATO invoked Article 5 for the first and so far only time. The chronology matters, however: the initial U.S. Operation Enduring Freedom was not simply a NATO war. NATO assumed command of the UN-mandated International Security Assistance Force in 2003 and subsequently expanded its activity across Afghanistan.

ISAF’s stated objective was to create security conditions in which the Afghan government could exercise authority and build its own security forces. Over time, security, counterterrorism, training, institution-building, and wider stabilisation became interwoven in a mission that lasted two decades. In 2015 it was replaced by the smaller Resolute Support mission, which ended in 2021.

The rapid collapse of the Afghan republic and the Taliban’s return after withdrawal exposed the limits of externally supported state-building. This does not mean two decades were identical or that no local social changes occurred; it means the security project failed to create a self-sustaining political order. Afghanistan therefore shows how an alliance founded for collective defence can become the organiser of a prolonged project outside member territory.

Libya 2011: a lawful civilian-protection mandate and a dispute over regime change

Libya differs legally from Kosovo. UN Security Council Resolution 1973 authorised “all necessary measures” to protect civilians and established a no-fly zone. NATO subsequently assumed command under Operation Unified Protector. The claim that the intervention had no UN mandate is therefore incorrect.

The critical question is what happened within that mandate. In 2016 the UK House of Commons Foreign Affairs Committee concluded that British policy rested on incomplete or inaccurate assumptions and that a limited civilian-protection intervention drifted by summer 2011 into an opportunistic policy of regime change without an adequate post-Gaddafi strategy. The UK government disputed that assessment, so this is a major parliamentary finding rather than an uncontested final judgment.

The aftermath is measurable: state collapse, militia warfare, civil war, weapons proliferation, and jihadist growth. Human Rights Watch also documented civilian casualties from NATO strikes and criticised inadequate follow-up investigation. Libya therefore shows that an operation can begin with a legally authorised protective purpose and still produce a political outcome that moves beyond the original humanitarian frame.

A symbolic editorial illustration of allied political decision-making, global military power projection, and the consequences of armed conflict. — **Symbolic editorial illustration.** The visual connects institutional decision-making, military power projection, and the consequences of war. It is not a photographic record of a specific NATO operation or evidence of the intent of any particular political actor. Image: THY-REALITY — original editorial illustration Original project editorial asset

Gladio: what is confirmed — and where the claim becomes too strong

The existence of post-war European stay-behind networks is not a conspiracy theory. European governments and parliamentary investigations acknowledged them in 1990; the European Parliament adopted a resolution on the Gladio affair, condemned secret armed networks outside normal democratic control, and expressed concern about possible unlawful interference in member states’ internal politics. The document explicitly referred to collaboration between national secret services and the NATO environment.

The same evidentiary discipline is nevertheless required here as with other covert operations. The existence of the networks and their links to Western security structures does not by itself prove that NATO as an organisation ordered specific terrorist attacks in Italy or elsewhere. Italian testimony and investigations themselves distinguish national structures, Atlantic coordination, and NATO’s formal command chain.

Gladio is therefore strong evidence for a more limited but politically important conclusion: the Cold War included clandestine security infrastructures operating with substantially less democratic oversight than ordinary public institutions. Stronger allegations of responsibility for particular acts of terrorism require a separate evidentiary chain for each case.

Ukraine: NATO enlargement is part of the story, but not the whole story

At the 2008 Bucharest Summit, NATO declared that Ukraine and Georgia would become members. Membership did not follow, but the political commitment remained. After Russia’s annexation of Crimea and the start of war in Donbas in 2014, NATO substantially expanded support to Ukraine through defence-sector reform, training, interoperability, logistics, cyber defence, and related capabilities.

Russia had long portrayed NATO enlargement and possible Ukrainian membership as central security threats. Western criticism of enlargement predates the war by decades, so it is not serious to dismiss every reference to the security dilemma as later Russian propaganda. Yet it does not follow that enlargement legally or morally compelled Russia to invade. In 2022 the UN General Assembly overwhelmingly condemned Russia’s use of force and demanded withdrawal.

Ukrainian agency matters as well. Ukraine is not merely territory between great powers; its political communities had their own preferences and increasingly sought Western security ties after 2014. A critical article therefore has to hold two truths together: NATO enlargement is a real part of the security context and Russian threat perception; responsibility for the decision to launch a full-scale invasion remains with the state that launched it.

American weight, the arms market, and the price of interoperability

NATO is not legally an American organisation, but the material asymmetry is large. NATO’s 2025 annual reporting estimated that the United States accounted for roughly 60 per cent of nominal Allied defence expenditure. The United States also supplies strategic enablers — nuclear deterrence, satellites, logistics, aerial refuelling, and command systems — that create real European military dependence.

That dependence has an industrial dimension. SIPRI estimates that the United States supplied about 58 per cent of imported major arms to European NATO members in 2021–2025, with combat aircraft and air-defence systems especially important. This gives a solid basis for arguing that the transatlantic security architecture creates a major U.S. export market. It is not the same as proof that every purchase is politically coerced or that European defence industry is marginal.

At the 2025 Hague Summit, Allies adopted a new commitment aimed at reaching at least 3.5 per cent of GDP for core defence needs and another 1.5 per cent for broader security and resilience spending by 2035. Supporters see this as correcting chronic European underinvestment; critics point to opportunity costs, defence-industry incentives, and the danger of treating a spending target as a proxy for actual security.

From the North Atlantic to the Indo-Pacific: defensive alliance or wider geopolitical bloc?

The 2022 Strategic Concept still defines collective defence as NATO’s essential purpose, but its tasks are wider: deterrence and defence, crisis prevention and management, and cooperative security. The document calls Russia the most significant and direct threat and, for the first time, treats China as a systemic security challenge. NATO has also deepened cooperation with Australia, Japan, New Zealand, and South Korea.

This does not mean that Asian partners automatically fall under Article 5 or that NATO is legally becoming a world organisation. It does mean that the Alliance’s political and security horizon no longer stops at North Atlantic geography. Cyber defence, space, supply chains, China, and the Indo-Pacific now form part of NATO’s strategic vocabulary.

Claim	What the documents support	Where the evidence stops
NATO is only a defensive alliance	Article 5 and collective defence are the treaty core; Article 5 has been invoked only once	NATO has also conducted Kosovo, Afghanistan, Libya, and other crisis operations beyond classic territorial defence
The West promised NATO would not enlarge	Documented 1990 verbal political reassurances included eastward non-extension language	There was no general binding agreement permanently barring Eastern European membership
Eastern Europe was forced into NATO	Applicants actively sought membership and accession requires consensus	Voluntary entry does not erase the geopolitical effect of moving a military bloc
Kosovo was a lawful war	NATO invoked a humanitarian purpose	There was no explicit UNSC authorisation; the Kosovo Commission called it illegal but legitimate
Libya was only civilian protection	UNSCR 1973 provided a legal civilian-protection mandate	A UK parliamentary inquiry found mission drift toward regime change and inadequate post-war strategy
Gladio proves NATO terrorism	Clandestine stay-behind networks and democratic-control problems are documented	Direct NATO command responsibility for specific terrorist acts requires a separate evidentiary chain
NATO caused the Ukraine war	Enlargement and Ukrainian membership are documented parts of the security dispute	That does not transfer responsibility for Russia’s invasion to NATO or erase Ukrainian agency
NATO is the U.S. military apparatus	The U.S. has disproportionate capability, spending, and arms-export weight	Decisions are formally consensual and Allies can block collective action
NATO is becoming global	The 2022 concept addresses China and closer Indo-Pacific partnerships	Partnership is not membership or a global extension of Article 5

The most defensible conclusion is therefore less comfortable than either slogan. NATO is a genuine defensive alliance for its members and a structure through which Western military power is organised beyond member territory. It is a forum of sovereign-state consensus and a system with pronounced U.S. material weight. Enlargement was voluntary for new members and changed the security balance with Russia. Interventions had humanitarian and security rationales and generated legal, civilian, and political consequences that official language often understates.

The open question is therefore not whether NATO can be reduced to one moral label. The more important question is: where is the boundary between the collective security of members and the power projection of a bloc — and who gets to define that boundary when one group’s security becomes another’s perception of threat?