Serious negotiations took place, especially between 1948 and 1949 and Denmark's then Prime Minister Hans Hedtoft-Hansen was very enthusiastic about the project.

Finland was left outside the negotiations since the peace treaty with the Soviet Union did not allow them to enter alliances without the approval of the Soviets.

The negotiations ran into a brick wall on the subject of NATO - Norway insisted that the Nordic Alliance be part of NATO, or at least negotiate to have military guarantees from NATO, while Sweden wanted the Alliance to remain strictly neutral. This is perhaps easy to understand - neutrality had failed Norway, but served Sweden well during the war.

Britain and the USA and NATO when it was founded proved unwilling to extend any gaurantees to non-member nations, and the Norwegians then withdrew from the negotiations to join NATO instead.

The Danes tried to keep the project alive, but Swedish interest waned a lot when Norway withdrew - there were little to no advantages for Sweden strategically to ally only with Denmark. Negotiations did not advance further, and in 1949, Denmark relented and also joined NATO, while Sweden remaineds neutral.

It could have been a realistic option had either Sweden or Norway been less stubborn on the issue of neutrality of the Alliance.