Different nations had different specific reasons, but in general neutrality was based on a decision to avoid subjecting the population to war.
They are called neutral nations. These countries were neutral during World War 2: Spain, Norway, Portugal, Ireland, and Switzerland.
Spain, turkey, and Sweden >>>>>>FOR A+ STUDENTS
belgium, poland, and all those countries in between
Spain, turkey, and Sweden >>>>>>FOR A+ STUDENTS
During World War I, Switzerland, Spain, and the Scandinavian nations remained totally neutral.
The united nations was created after world war 2
What happened to the nations who lost world war 2?
. . . but the US was not a neutral nation in world war 2. The US was one of a number of nations that composed the 'Allies' in declaring war on the empire of Japan.
Not at war
Switzerland, and Sweden maintained neutrality. Spain was in the grip of Franco, and kept quiet.
Switzerland, and Netherlands were neutral during world war 2
In Europe, the nations that managed to remain neutral were Sweden, Spain and Switzerland. In Africa, all countries were linked to either Italy, France or Britain so none of them remained neutral. The Latin American countries remained largely neutral. Asian countries were practically all dragged into the war, either because they were invaded by Japan or because they were colonies of Japan or one of the Allied nations.