In the middle of WW2, a series of international conferences posed the basis for the economic and geopolitical post-war period: Tehran (December 1943), Bretton Woods (July 1944), Yalta (February 1945) and Potsdam (July 1945). Less known, but equally important, are two treaties that delivered the international security architecture that has lasted until today. On 4 March 1947 France and the UK signed the Dunkirk treaty of mutual military assistance, for cases of aggression from external forces (with Germany or the Soviet Union being top of the list). And, crucially, the Western Union treaty was signed in Brussels on 17 March 1948, between the UK, France, Belgium, the Netherlands and Luxembourg.
The Brussels treaty, scheduled to remain in force for 50 years, established cooperation amongst its five signatories in the military, economic, social and cultural spheres. The Brussels treaty is the embryo of the subsequent North Atlantic Treaty Organisation (NATO), of April 1949, with the US joining the alliance and its expansion to other European countries as well as Canada. While the US has always had a predominant role in NATO, its embryonic form dates back to the Brussels treaty and its mastermind was Ernest Bevin, the UK foreign secretary, so one can credibly argue that the US in fact “joined” the organisation, which still today is based in Brussels and has always been led by European leaders.
Following the birth of NATO, the global security equilibrium has been based on the credibility of its “Article 5,” which stipulates that an aggression against any NATO country would entail the response of all the others, in particular the US (which had guaranteed its nuclear umbrella). Just as the US fought on two fronts during WW2, so NATO has “stabilised” the trans-Atlantic front, while the nascent QUAD is replicating the same approach towards the Pacific. For this reason, the US has de-facto extended “Article 5” to the Pacific, with the promise that if China invaded Taiwan, this would trigger a US response (in spite of the official “One China Policy”).
This long background analysis is necessary in order to make two assertions. First, the threat that the US may “leave” NATO is a credible one, if a US president were to decide to pursue it. Clearly, from a practical standpoint, if the US were to leave NATO, this would mark the end of the alliance, which would not have the means to support its aims, considering that the US spends in defence as much as the next 10 largest-spending countries summed together, including China, Russia, India and Saudi Arabia. But from a legal standpoint, the US may leave NATO, thus forcing all the other countries to multiply by a large factor their military spending.
Second, the credibilityof Article 5, even more than its existence, is the cornerstone of the global security equilibria, both in trans-Atlantic and trans-Pacific terms. If the US were no longer perceived as ready to intervene to defend a European country under attack, or to defend Taiwan in case of a Chinese invasion, then the geopolitical rivals of the US would easily “catch their prey.” There is even a cross-reading between the two sides: the US cannot credibly be said to be willing and able to defend Taiwan at any cost on the Pacific front if it does not demonstrate a willingness to defend a European country within its sphere of influence from Russian aggression, with Ukraine being the example at hand. Hence, the inevitability of the approval of the latest USD 95bn military assistance package deliberated by the US Congress, despite months of posturing.
In this way, isolationism in the US is not compatible with the responsibility of being the ultimate guarantor of the world’s geopolitical equilibria.
