Iraqi ruling party - Baath is a SECULARIST party founded by a Christian Michael Aflaq. Read more about Baath Party
9/11 terrorists were no affiliated with Iraq, they were affiliated with Saudi Arabia. Bin Laden is not from Iraq, he is from Saudi Arabia. Taleban was not supported by Iraq, he was supported by Saudi Arabia (and at times by United States).
The main area of Iraqi troublemaking is support for the secular part of Palestinian movement. The main asset of Iraq is oil. Control of Iraq will strengthen American hand versus Saudi Arabia and Iran. This in tern will secure the contron of oil producing areas from Central Asia to the Middle East. If Venezuela is put in order, America will have upper hand versus Europe, euro will not be able to challenge dollar and the threat to the leading position will be postponed.
The main problem is that the conquest of Iraq is a very risky operation and that it will undermine secular movements in the Arab world versus Islamists.