The invasion was ordered by the executive branch, correct?
Maybe there should be a law against using the office of President for personal gain.
Yes it was ordered by the executive branch, because he is the Commander in Chief. But the issue you raised is whether the war is "illegal." I understand having that opinion, but it will not hold up in any court, military or otherwise, because Congress endorsed the war, at least twice, after it started, and we have a multinational force. I think the "illegal" argument would be much stronger if the UN voted that it was unauthorized.