Nations if they want peace.
Should always be prepared for war.
A strong defense is a good deterrent.
Also a good deterrent is staying out of stupid crap and minding your own business. Sweden was well over a century and Finland was 80 years out of the war business and had functioning national models.
Now their feminist and beta male leaders have managed to flood Sweden with Africans and moslems. Grenade and bomb attacks happen daily. Women are certain to be molested, groped and raped if they walk the formerly peaceful streets.
And now, both countries have managed to push their way into a war. Sweden was able to stay out of WWII. But couldn’t avoid Ukraine.
A solid defense is half the equation for peace. The other half is avoiding alliances and strife that does not involve your own people.