People have used scorched earth attacks against their enemies, but that's if the enemies have defined territory. Does it seem reasonable that governments would engage in a nuclear spasm which would mostly destroy human territory? This is a real question.

I can imagine a nuclear spasm happening, but I was around during the cold war, and read relevant science fiction.

I realize there were some close calls[1], but is the world still as delicately balanced? Could wizards make sure the nukes stayed in their silos? My guess is that wizards have the power, but possibly not the organizational ability.

[1] Fanfiction about the unlikely absence of WWIII being the result of wizard activity?