3 ms·Collective defense aka casus foederis as defined by Article 5 of the North Atlantic Treaty.by voxadam 8mo agoCollective defense aka casus foederis as defined by Article 5 of the North Atlantic Treaty.chistev 8mo agoEven an attack by one of its own members that's its leading military and financial force?surething 8mo agoAbsolutely. Yes.