See also Munich Agreement
The Munich Agreement was a settlement permitting Nazi Germany's annexation of portions of Czechoslovakia along the country's borders mainly inhabited by German speakers, for which a new territorial designation "Sudetenland" was coined. The agreement was negotiated at a conference held in Munich, Germany, among the major powers of Europe, without the presence of Czechoslovakia. Today, it is widely regarded as a failed act of appeasement toward Germany. The agreement was signed in the early hours of 30 September 1938 (but dated 29 September).If the EU gets its act together, then stationing a few special weapons under Ukrainian control might defuse the situation. They gave up their own in return for a guarantee. We must make good on that promise, or return the capability to them. And let Putin know that those are the two options - which would he prefer?
UPDATE : Ukraine calls on NATO to make good on guarantee.
1997 Charter on a Distinctive Partnership between the North Atlantic Treaty Organization and Ukraine:
14. NATO Allies will continue to support Ukrainian sovereignty and independence, territorial integrity, democratic development, economic prosperity and its status as a non-nuclear weapon state, and the principle of inviolability of frontiers, as key factors of stability and security in Central and Eastern Europe and in the continent as a whole.
15. NATO and Ukraine will develop a crisis consultative mechanism to consult together whenever Ukraine perceives a direct threat to its territorial integrity, political independence, or security.
16. NATO welcomes and supports the fact that Ukraine received security assurances from all five nuclear-weapon states parties to the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) as a non-nuclear weapon state party to the NPT, and recalls the commitments undertaken by the United States and the United Kingdom, together with Russia, and by France unilaterally, which took the historic decision in Budapest in 1994 to provide Ukraine with security assurances as a non-nuclear weapon state party to the NPT.