What separates Britain's historical commitments to Belgium and Poland from NATO's position toward Ukraine?
Short answerBritain had explicitly promised protection in the earlier cases, whereas NATO had made no equivalent defence guarantee to Ukraine.
NotesThe distinction rests on the commitment actually made rather than on sympathy or strategic importance. Britain had given its word to protect Belgium and Poland in the historical cases raised by the viewer. NATO had not extended the same promise of collective defence to Ukraine. Alliance obligations turn on formal guarantees: political support and military assistance do not by themselves create an identical treaty duty.