NATO has been ‘adapting’ for a decade and has made significant progress in meeting the coming challenges to Europe defence. However, power is relative and the nature of future war across the multi-domains of air, sea, land, cyber, space, information, and knowledge, allied to the accelerating speed of war, also reveals profound Allied weaknesses. Whilst the Americans are increasingly overstretched trying to cover the expanding space and technology of warfare, Europeans are decidedly under-stretched, unable, or unwilling to meet the demands of defence, too often seeing defence as a budget to be raided for domestic political concerns. Ultimately, NATO is in the business of deterrence, for if it fails defence seems unlikely, short of a rapid descent into all-out nuclear war. Europeans must thus understand that NATO is essentially a European institution, and it can only fulfil its mission as a defensive Alliance if they give the Alliance the means and tools to maintain a minimum but credible conventional force and nuclear force deterrent.