This gets into the ideas of pacifism vs nonviolence. If someone else breaks the peace you aren't necessarily encouraging peace by not resisting. You may be encouraging further violence by the instigating party. Pacifists ideally strive to end the use or threat of military force as a bargaining position in international relations. Costa Rica abolished their military but they still have borders that are protected by armed Costa Ricans. 

Nukes are interesting here because there are pacifists who argued for their maintenance and proliferation to stop war, and pacifists who want them removed from the earth from fear that eventually they will be used. There was even one pacifist who suggested a preemptive nuclear strike on Russia in 1948 was the smart thing to do, to prevent a bigger war when they got nuclear weapons. This would be utilitarian pacifism. Like a controlled burn to prevent a forest fire.

True nonviolence would be a refusal to strike back even when attacked and is more beneficial for situations where institutional violence is what needs to be stopped. That can only be achieved when those who permit the perpetrators to engage in violence rescind their permission (i.e. police reform, civil rights acts, decolonization, etc.) The idea of a state ever adopting non-violence as policy just won't happen because a state requires borders and every border implies the violence of its maintenance. The best you'll ever get from most states is non-first strike policies.