NATO is cited as the prime example of nation-state cooperation and collective action in international law. The treaty is less robust than supposed. It was little more than an ad-hoc alliance based on common interests, so it might not last much longer in the future. One of the problems in collective action is burden sharing.

NATO formally united the Western European and North American militaries together to defend against a Soviet invasion.
The diplomatic and military cooperation accomplished its goal of deterrence and prevention of a major war.

NATO needed to keep a unified front against any aggression, without smaller members bolting or declaring neutrality, which would weaken the integrity of the alliance and encourage attacks

France partially defected from the American-led alliance in 1966. They withdrew from the NATO command structure and created an independent nuclear force. France declared it was the leader of the “Third Way” – the alternative between the US and USSR. Fortunately, few took the French seriously, so the French remained within the NATO alliance.

NATO greatest achievement was diplomatically resolving a coordination problem. Each ally needed to agree upon a command structure, communications, transportation, interchangeable equipment and ammunition, etc.

As a simple example, using standard ammunition lowers costs of maintenance and increases interchangablity. It is better if all nations agree on a standard bullet (such as the 5.56mm NATO) rather than three armies uses three types of ammunition – 5.56mm, 7.62mm, and .303 cal – which are not compatible.

This allowed American, British, and West German armies to coordinate operations with one another. NATO, unlike many past alliances, was not simply the sum of its parts, but a more effective organization when these parts united. NATO provided an effective framework for coordinating multi-state activities for everyone’s maximum security benefit.

NATO, during the Cold War, shared defensive burdens. We can measure this through military spending. Empirical research by Paul Diehl and John Oneal suggested that the 15 member states achieved partial success with this, but still faced the problem of free-riders. According to them, three factors played a major role in determining the relevance of a NATO member – their economic size, their proximity to Soviet controlled borders, and economic integration with threatened members.

The US took on the heaviest burden, paying an average of 8.1% GDP on defense between 1950-1986, while the weighted average of its European allies was 4.7% GDP. NATO was primarily a US-UK-West German Alliance, while other states, such as Italy, Belgium and others were free riders.

Since the end of the Cold War, the US reduced its defense budget to under 4% of GDP and the European Nations reduced theirs to under 3% on average. European militiaries are no longer capable of independent operations, as NATO action in Yugoslavia and Afghanistan showed. Few European troops are combat ready and they lack logistical capability to deploy them out of their home countries.

Today, NATO is a defensive alliance without a Soviet threat. It’s early cohesion – which is overstated in the first place – was a coincidence of interests. The Western Europeans faced real and imminent security threats, so had little incentive to ‘wobble’ or bolt from the alliance. Economic interdependence, partly from GATT, made the defense of Western Europe an economic necessity for the USA. As such, this was not altruism, but an alliance of mutual self-interests.

The Eastern Europeans may view NATO as a way of securing their countries from a rise of another Russian Empire. However, the Western Europeans are clearly no longer concerned about Russia, so it is in their interest to stop cooperating with the US and halt the sharing of security burdens.