Two years ago, together with a broad group of former officials and experts, we warned that, in the absence of a new military and political strategy for the Euro-Atlantic region, there was a risk that stability would weaken and security would break down. Sadly there are clear signs that this is happening, with Europe now beset by its most serious and deadly crisis in decades.

In Ukraine, more than 5,000 people have been killed, 10,000 more have been wounded, and 1.2 million have been forced from their homes. If we don't stop the killing and address the mounting divisions in Europe, our generation may claim to have ended the Cold War without securing a peaceful future.

No security architecture, old or new, can succeed without leaders who are committed to addressing and resolving core issues. No process or structure, however elegantly designed, can substitute for bold political leadership and agreement on shared goals.