Interest in 'World War III" spikes after the US airstrike kills Iran's Top General

From what I've read and looked through, the Pentagon had intelligence and clear evidence that Soleimani had arrived in Iraq to continue his efforts to stage attacks against American forces, the U.S. embassy in Iraq, and other American contractors. After the forces he commanded killed an American contractor among others, the U.S. retaliated. There's a point where we must stand our ground, even if it risks war. I doubt that World War 3 would happen from a U.S.-Iranian conflict, as most nuclear-capable countries in the world understand that an all-out conflict would result in the sure destruction of everyone involved.