We really are back to elements of the 1920s and 1930s in tandem, it seems, even if markets still don't grasp that underlying reality. Actually, markets are starting to grasp the 20s parallel when it comes to social unrest, political breakdowns where political parties are either compromised or irrelevant, and popular 'movements' emerge spontaneously instead (luckily so far absent charismatic leaders). Indeed, Wall Street appears to be all in -- by which I mean exacerbating -- it. The smart money also sees the end parallel of the everything bubble and a Fed raising rates anyway. Some focus on a 30s background where Russian President Putin says on European security: "It's already clear…that Russia's principal concerns were ignored" and that the West is using Ukraine as a "tool to hinder Russia".
There seems no way to bridge the fundamental differences in interpretations of the 1975 Helsinki European security agreement that says all states are sovereign and free to decide which defence alliance they want to join, and that no state should join an alliance seen as a threat by another. Which clause has primacy? The former, if you view NATO as defensive. The latter, if you see NATO as offensive.