In a completely new security context after Russian agression against Ukraine NATO is reviewing all fundamental principles, which has driven its decisions over the last two decades. Enlargement, the Alliance’s primary policy to realise the vision of a Europe whole, free and at peace, should be — and has been — no exception.
With the first post-Cold War enlargement in 1999, which included Poland, the Czech Republic and Hungary, NATO acted on its commitment to the Open Door Policy. Based on Article 10 of the Washington Treaty, the new policy was launched in 1994 in parallel with a new Partnership Policy. Since then the Alliance has grown to 28 members, overcoming the post-Yalta divisions of the European continent into spheres of influence.