How would the war change if Denmark, Norway, Sweden, and Finland formed an alliance on 2 September 1939?
Short answerA mobilized Nordic armed-neutrality bloc could make German invasion much harder and would probably receive British and French support.
NotesThe alliance would have to declare armed neutrality and actually mobilize its reserves. Reinforcements from the other Nordic states could make the invasion of Denmark far more difficult than it was historically. Norway and Sweden would gain coordinated depth, while Finland adds another state able to complicate pressure from the Soviet Union or Germany. Britain and France would likely cultivate the bloc as a friendly neutral barrier rather than treat each country in isolation.