Ah. I don't tend to see Iran-Contra as something that affected things much over the long run. True, trading arms for hostages would seem to encourage hostage-taking and probably it did somewhat. But in the big picture the larger Sunni Islamist movement theorizes Shia Muslims as part of the problem along with Jews and West, and has avoided taking any inspiration or lessons from anything having to do with the Islamic Revolution in Iran. You would think America's humiliation at the hands of Iran through the hostage taking and Iran-Contra would make for a big talking point with Islamists and Arabs in general, but in fact it rarely comes up in Arab state propaganda or in Islamist documents discussing how to beat the West (in the latter, Mogadishu and Lebanon loom large instead). Granted it's unlikely that Reagan could have known that the regional effects of his actions in Iran were inherently self-limiting because of confessional (and probably also ethnic) differences, since most experts at the time expected the opposite to occur, so he still gets bad marks for poor judgment.

I was thinking more of mistakes that were actually bad enough to substantially change our position in the country as Carter's did, and to me the only thing that comes close is the CIA-backed coup (under Truman) of Mossedegh.

I thought the policy to encourage and support Iraq in waging the Iran-Iraq War began with Carter? I cringe at the prospect of searching for a detailed objective history by Googling however. Anybody know for sure offhand?