the organisation, along with its unrivalled military capabilities and superpower reach on the one hand, and the existence of the political and military decision-making structure and process embodied in NATO on the other. It is this combination which makes NATO profoundly different in the field of security and defence from the European Union, notwithstanding the fact that 22 EU members out of 28 are members of NATO (and vice versa).
It was noted in the previous assessment on the “Effects of Finland’s Possible NATO Membership” (21 December 2007) that “NATO’s original task, prevention of an attack from outside, is no longer as central…as it used to be. Within NATO, it is estimated that, in the next ten years at least, the Alliance will not face such a military threat which it would not be able to respond to”. This is no longer the case on both counts: Article 5 is back at the centre of the Alliance’s concerns, and new measures were taken at the NATO Summit in Wales (2014) or are under active consideration to enable the Alliance to credibly meet developing military threats, notably in the Baltic and on NATO’s Eastern border. The NATO Summit in Warsaw in July 2016 will develop these measures further.
On the initiative of European members of NATO, Article 5 was invoked in the aftermath of the 11 September 2001 attacks against the United States.
Article 4 may be less well known to the broader public but is of substantial practical consequence. “The Parties will consult together whenever, in the opinion of any of them, the territorial integrity, political independence or security of any of the Parties is threatened”: this instrument can thus be invoked by any member, and on occasion this is what happens in practice. Lithuania and Poland did so in 2014 in the face of Russian operations in Crimea, and Turkey has done so three times in recent years (in 2003 during the run-up to the US invasion of Iraq, in 2012 when a Turkish combat aircraft was shot down by Syria, and in 2015 during the siege of Kobane on the Turkish-Syrian border). In itself, Article 4 is fundamentally no different from other consultative instruments, in the UN or EU frameworks for instance. As it can represent a step on the ladder to Article 5, it has a quality of its own, however. This also helps explain why it is invoked relatively rarely: most member states usually understand that this instrument must not be abused.
THE ORGANISATION. If one strips away what NATO has in common with other treaty organisations relevant to Europe, four elements stand out.
