If you're being attacked, I'm not sure what international law has to do with it. A country has the right to defend itself -- it doesn't require the UN to grant 'permission.' If you are in the midst of being attacked, waiting for the UN or some other disfunctional body to 'approve' would be like asking the teacher for permission to defend yourself while you're getting your face pounded in. Countries are sovereign. They shouldn't need permission to defend themselves when they are under an immediate threat.