War is perhaps illegal, except in self-defence, but certain people interpret "self-defence" to mean "defence of (national) interests", but also, belt-and-braces, they don't actually declare war any more and claim that what they're doing, killing and maiming people, bombing hospitals, television studios, water purification plants, isn't a "war". Also, Geneva Convention does not apply because the victims are "unlawful combatants" or some such bullshit.