Nato's biggest enemy hides within

Nato remains the most powerful military alliance, but in terms of its core political values it has never been so vulnerable.

Discussions about increasing the military budget or responding to the ambitions of other powers will be in vain if the members of the alliance do not rediscover what they are supposed to defend, or, as the North Atlantic Treaty makes it clear: "the freedom, common heritage and civilisation of their peoples, founded on the principles of democracy, individual liber...