@Maggot
Yes there are rules. War crimes are prohibited and attacks on civilians are one of them.
Still, Hardoria put the blame on Sarjas (while it was Haldoria), Sarjas was annexed by the Empire in retaliation. Second problem : with all the proofs gone, Haldoria will never get what they justly deserve because of this.
You're also right about Robert's attack, it's also a war crime from Elizabeth, but very few people are actually aware of her abilities (Mireille herself wasn't aware she was capable of doing that), so Robert took the blame.