Iran and Iraq
I think Matt Yglesias is spot on; anĀ Iranian style government in Iraq means little or nothing to the attitude of that government towards Iran. In international politics, and especially with respect to authoritarian countries, birds of a feather do not necessarily flock together. I’m not even 100% sure that we can rely on Iraq to be less hostile towards Iran than the US is, because there are some good reasons for the two countries to be regional rivals. That said, Iraq isn’t going to be able to play in the same ballpark as Iran for a long, long time, so any rivalry will probably be muted for a while.
Unless, of course, the US gives the same treatment to Iran that it has given to Iraq. . .