Start with “they probably violate the UN Charter, along with international law”. But such concepts and arguments seem so quaint anymore.

Well Iran recently slaughtered tens of thousands of peaceful protesters. And guards from the islamic republic of Iran went as far as going into hospitals to find wound protesters and execute them.

A few concepts may be quaint but I guarantee you that they're even quainter when a country is ruled by sharia law, like Iran.

If you invade countries that mistreat their citizens, the US is the big, loud one over there near Mexico and Canada. Have fun.