The premise of this thread it that when a party starts a war and loses, the defending side should be allowed to finish it. In the cases of WW I, Korea and Vietnam the aggressors, respectively Germany/Austro-Hungarian Empire, North Korea and North Vietnam started wars. The wars ended in armistices, not in military victories. In all cases complete victory was possible but the West, being “nice” left the losing side to their own devices. In all cases it has leapt us to bite us.
WW I (armistice) – This case is perhaps the least clear. The Austro-Hungarian Empire, tied by treaty and history to Germany (only recently Prussia and other principalities) tried to take over the Balkans, lured by the chaos surrounding the murder of the Archduke of Sarajevo on June 28, 1914. (source). After a long war with unprecedented bloodshed the Austro-Hungarian Empire was split into Austria, Hungary Romania, Bulgaria, Albania and Czechoslovakia, and the Balkans reconstituted into Yugoslavia. However the core of the countries remained intact and were not occupied. The terms of this armistice did not sit easily with a still-intact and independent Austria and Germany. They covertly did not comply with the disarmament mandates of Versailles. All else is history.
Korea (armistice) – Probably the strongest case. Korea was historically under the sway of either Japan or China (source). In or about 1910 Japan seized control. When WW II ended Korea was partitioned between the northern half, occupied by the USSR and the southern half, occupied by the U.S. There was, to my understanding, little reason for this generosity to the U.S.S.R. since they took astonishingly little part in the defeat of Japan in the war. In Europe, at least a colorable argument could be made that they earned a share of the spoils, and effective control of Eastern Europe. When NK invaded in 1950 there was little reason for not conquering and holding NK, reuniting it under South Korea’s military dictatorship.
Since then, NK has clearly not found the status quo acceptable. They are now a nuclear power, leaving the West with little choice but surrender or a full-scale war before NK poses a mortal threat to the civilized world.
WW II – This is an example in the opposite direction, of what happens when there is total victory, mostly by the civilized world. While we have not had “kumbaya” perfection (see above regarding Korea, and also other small wars such as Vietnam and the Middle East), the world has by and large not had major wars. Victory was total. Japan and Germany are not a threat to world safety nor are they likely to be.
Israel (armistice in 1948 and 1956, victory in 1967 and 1973) – Another good example. 1948 and 1956 ended in standstills. The Arabs kept on attacking. In 1967 they closed the Straits of Tiran, threatening to throttle Israel’s imports of oil from Iran. Israel obliterated Egypt’s air force on the ground. The war lasted six days.
Since then the rest of the world has sought to give the Arabs a do-over. Trump finally recognized Israel’s choice of capitals. The Arabs should have sued for peace when they had a chance. Israel won and the world “boo-hoos” at their exercise of the victory. If they were anything like North Vietnam, Myanmar or other victorious countries there would have been a bloodbath.
Summary – A loss in war should severely and permanently penalize the aggressor. Germany and Japan were reduced to second-rate, though affluent powers. I don’t think that’s such a bad fate for the people of the Arab world, as opposed to their “leaders.”