Recently many people, including many highly respected people and corporations, have come out saying, contrary to what the W administration has said, that Iraq is in civil war. Now, generally, in my opinion the W administration has done very little right, except make political appointments, which, with a few exceptions, have almost all been good. However in this case I must agree with the W administration, this is not a civil war, except I don't agree with the administration for the reasons that you might think.
To be a civil war there must be a legitiamate government force and there must be an organized force trying to overthrow the government. Now there are roughly four sides currently in the Iraq war - the U.S., the Maliki Iraqis, the Sunni Iraqis, and the Shia Iraqis. Not to mention all of the little sub-factions present in Iraq.
To start with the "rebellion" force is far from organized - the rebellion has two or three factions if not more. Second, I do not think that the Maliki Iraqis are a legitiamate government. They have only been in power for a few months, they're largely supported by the Americans and Allies, and they I don't think that they are recognized by the Iraqis as being a legitiamate goverment. Its not really my decision as to whether or not the Maliki government is legitiamate or not, it is the decision of the Iraqi people.
The last decendant of Julius Caesar to rule Rome was Nero Claudius Caesar Drusus Germanicus - Nero. Following him were three or four short term "emperor" - each ruled for a few months only. Then after two years and four leaders Flavian Vespasian ascended the throne followed by four of his decendants. But by the time that AD150 rolled either the Flavians were weakening or they were outright replaced.
Were the short-term emperors legitiamate emperors - well they certainly thought so. But they probably spent as much time trying to solidify their power base as they did trying to learn the Imperial Roman Goverment.