Designs,
Iraq is predominantly, though not exclusively Shia, unlike Iran which is almost exclusively Shia, so there is a natural fraternity there. Shia influence is therefore greater as Iraq is 60% + Shia, this is further overlaid with complicated tribal allegiances, The Kurds are a mixture of Shia and Sunni. This is to my mind where Bush and co singularly and miserably failed before their invasion, the preparation for peace was risible; the consequences were and are horrendous.
There is no doubt that Iran foments mischief in places such as Syria and Lebanon, they also loathe the Saudi's and The Taliban. What is also becoming clear is that the people of the Middle East detest their kleptocratic rulers and want change irrespective of the branch of Islam they subscribe to. If the west helps this and supports this awakening, the region can and will change, it will anyway.
A very good friend of mine who is an Iranian and still has family there is convinced that the Old Guard in Iran will change and or be overthrown.
David