Since we have nothing else to do at the moment, I thought I'd give a quick overview of population groups in Iraq and their politics, from what I have seen and read and heard.
Overview:
80% of Iraqis are Arabs, the rest are mostly Kurds. The remaining 5% are Aramaeans/Chaldaeans, Turkmen and Mandaeans. Kurds are an Iranian people. Aramaeans, Arabs, and Mandaeans are Semitic peoples. There used to be a huge Jewish minority in Iraq but the Jews fled starting in the 1930s (when Iraq allied with Germany). Since 1955 or so Iraq is more or less Jew-free.
Locations:
The Kurds and Turkmen live in the north-east, at the Turkish and Iranian border in a region also stretching to the Syrian border in the west. Kurds have good ties to Iran and Iran is very popular among the Kurds. Turkmen have good ties to Turkey.
The Arabs live in the rest of the country, from the south along the rivers to the Syrian border in the north-west.
The Aramaeans and Mandaeans used to live mostly in the non-Kurdish part, but have since mostly fled to Jordan and Syria or (in the case of the Aramaeans) to the Kurdish region.
The Jews used to live mostly in Baghdad and Mosul.
Languages:
The Arabs speak Arabic. The Kurds speak Kurdish (an Iranian language, like Persian). The Aramaeans/Chaldaeans traditionally spoke Aramaic but increasingly speak Arabic or Kurdish now, a fact much lamented by the Kurds who celebrate multikulturalism. The Turkmen speak a Turkish language and/or Kurdish. (Note that Turkish and Kurdish are not related.) The Jews used to speak Aramaic but their dialect was replaced with Modern Hebrew in Israel.
Religions:
Most Iraqis are Shiite Muslims (about 60%). The rest are mostly Sunni Muslims. There are many Christians and some cities have dedicated Christian quarters where only Christians are allowed to buy property.
Political Demographics:
Politically, Iraq consists of six camps. Listed are here the groups from majority to minority.
1. Moderate Shiites. Their religious leader is Grand Ayatollah Al-Sistani (an Iranian immigrant to Iraq from decades ago). They are about 40% of the population and can be found everywhere from Baghdad to the Shiite south. They supported the invasion but want the Americans to leave. They are also suspicious of Iran's interference in Iraq but see Iran as a counterbalance to the Americans and foreign Sunni Arabs (Saudi Arabia).
2. Radical Shiites. Those are the supporters of the false cleric (he doesn't have an actual title) Muqtada Al-Sadr. They are also called "Sadrists" and represent about 20% of the population. They supported the invasion, love Iran (but occasionally become suspicious of Iran's influence), and want the Americans to leave. They were originally part of the insurgency against the Coalition but have abided to a cease-fire for some time now.
3. Kurds and Turkmen, plus lots of Christians who fled to the north. They represent about 20% of the population. Apart from perhapt the majority of the Christians this group supported the invasion and want the Americans to stay until everything is stable.
4. Baath-supporting Sunni Arabs. They represent about 10% of the population and can be found in Baghdad and the region around Tikrit. They were against the invasion and want the Americans to leave. The famous shoe thrower is one of their number. His action against President Bush was supported by this group and the Sadrists and opposed by pretty much everybody else.
5. Tribal Sunni Arabs. They represent about 10% of the population and live in the north-west (the Sunni Triangle). They were against the invasion but want the Americans to stay. They are now the most pro-American group and have even offered to fight alongside America in Afghanistan. They fear Shiite militias (Sadrists) and Wahabi terrorists (Al-Qaeda). Like the Kurds they believe that withdrawing troops too early will lead to civil war.
6. Intellectual Elite (mostly Sunni Arabs). They can be found in Baghdad. Their number is very small but they hold many government offices. They supported the invasion and want the Americans to stay. I am not giving a percentage here because they are already included in the above percentages. I don't know how much of each percentage I would have to deduct to get the number.
Other groups, like Al-Qaeda, are not home-grown and have little support among Iraqis.
Opinion Statistics (Informed Guess):
Supported invasion: 80%
Against invasion: 20%
Want Americans to stay: 30%
Want Americans to leave: 70%
Support shoe thrower: 30%
Against shoe thrower on ideological grounds: 30%
Against show thrower for practical reasons: 40%
Against Iranian influence: 20% (Sunni Arabs)
For Iranian influence: 20% (Sadrists)
For Iranian support: 40% (remaining Shiites)
Neutral but careful: 20% (Kurds)
Opinions on Israel:
Kurds, Turkmen, Christians (20%): between friendly and no issues
Tribal Sunni Arabs (10%): don't care much, improving as Al-Qaeda became biggest enemy
Baathist Sunni Arabs (10%): hatred, but prefer Israel over Iran
Sadrists (20%): whatever Iran tells them
Other Shiites (40%): hatred
Saddam even spoke up against Hizbullah in prison.
(Note that the Shiites are the population group who had the least contact with Jews when Jews still lived in Iraq. Most Kurds and Sunni Arabs remember stories about their grand parents being friends with Jews.)