[gerdesj]

Sweden are joining NATO right now due to the Russian invasion of Ukraine and so did Finland. Both of them border Russia and did not join NATO in the past to try and avoid any form of escalation.

Switzerland may have been formally neutral during WW2 but some individuals had other ideas. Was Switzerland neutral through WW1? My 100 years thing goes back to 1924, so post 1914-18.

[dukeyukey]

Joining NATO does not mean they are involved in a war. Not yet at least. And Switzerland was not involved in WW1 - the last war involving Switzerland was in the 1840s.

You could look at Iceland too. It was declared it's own country in 1918, and other than a brief, zero-casualty "occupation" during WW2 has never been involved in a war. It has no military and no legal mechanism to be able to declare war.

[euroderf]

And the occupation was friendly.