system
Given the following post, respond as if you're commenting on Reddit:
human
Under international law when can one country invade the other?

I was watching a Hitchens debate the other day and he stated theat there 4 ways a coutry can lose its sovereignty: violating the Genocide Convention, violating of the Nuclear Non-Proliferation Treaty, granting safe harbour for terrorists, and invading another territory. I couldnt find andy crecidble sources supporting this claim, however if it were true wouldnt the Iraq war be a just war?
gpt
The UN charter prohibits the use of force with two exceptions: self-defense (including anticipatory and mutual self-defense) and with the authorization of the UN security council. Any other invasion or attack is technically illegal under international law.