Stop pending the argument that "it's politically impossible / toxic / whatever / unenforceable etc.", that's a dumb argument.
Just take politics out of the equation! Or more precisely, take "democratic choice" out of this particular policy decision!
If countries amend their constitutions to disallow any party or individual not in support of this to even be part of any election, then this particular aspect would simply not appear in political campaigns. Have "dark room" deals in most countries of the world put this into place and move on.
And once the major international players are on board, for any country not playing the same game, just kindly point the missiles at them!
In the end, most national governments would approve of such taxation because they'll have the opportunity to formulate it in their own terms and slightly increase national budgets (maybe investing a bit more in the military and gaining an advantage over their neighbors that don't do it... ugly but any incentive in the right direction helps). And multinational corporations would also not mind it much if it's done across the board, without favoring anyone... and actually corporations could be "hired to enforce the tax" in more advanced schemas, offering opportunities to profit while punishing misbehaving countries.