Not sure this has been brought up:
The Budapest Memorandum on Security Assurances refers to three identical political agreements signed at the OSCE conference in Budapest, Hungary on 5 December 1994 to provide security assurances by its signatories relating to the accession of Belarus, Kazakhstan and Ukraine to the Treaty on the Non-Proliferation of Nuclear Weapons(NPT). The memorandum was originally signed by three nuclear powers: the Russian Federation, the United Kingdom and the United States. China and France gave somewhat weaker individual assurances in separate documents.[1]
The memorandum included security assurances against threats or use of force against the territorial integrity or political independence of Ukraine, Belarus, and Kazakhstan. As a result of other agreements and the memorandum, between 1993 and 1996, Belarus, Kazakhstan and Ukraine gave up their nuclear weapons.[2]
https://en.m.wikipedia.org/wiki/Budapest_Memorandum_on_Security_Assurances
Seems like Putin has invalidated that policy.
Can we perhaps maybe shoot down their missiles in Ukraine?