No Country was immune during WWII...Even Sweden, which maintained it's neutrality, let the Wehrmacht transport equip. and ammo, on it's rail lines...The Swedes technically never got involved in International Affairs since the Napoleonic Wars, around 1815. BUT had some involvement. It got away with it, from an Aryan Race point of view. Norway Caved, and Finland fought as long as it could, but never caved, as it was Russian influenced, and never signed the Pact Of Steel.
C'mon FA....The Swiss had an armed citizenry. The German Field Marshall told the Swiss Premiere, I will invade Geneva with 1,000,000 men.
The Swiss replied "Fine, EVERY Swiss citizen will only have to fire three times." (paraphrased), but the Germans knew the Swiss were ALL ARMED...Right down to the Dog Catcher. It was not a direction they wanted to go....They had other DISARMED countries to get.
Kinda a Mexican Standoff, with the Swiss and Nazi's. But the Swiss did backdoor enable in other ways... I'm sure Tom will have even more to add.
Right up until Russia,....and we know how that turned out....