From the invasion of Iraq to ISIS
Subject: De-Ba'athification, Camp Bucca and the traceable lineage of the Islamic State
ISIS did not appear from nowhere. Its lineage runs directly through the organisation that formed in occupied Iraq, and the conditions it grew in were made by decisions the occupation authority documented itself.
01The allegation
The chain is continuous: Zarqawi's Jama'at al-Tawhid wal-Jihad, which pledged to al-Qaeda in 2004 and became al-Qaeda in Iraq; then the Islamic State of Iraq; then, after expanding into the Syrian war, the Islamic State of Iraq and Syria, which declared a caliphate in 2014 and captured Mosul.
02Origin
Coalition Provisional Authority Order Number 1 removed senior Ba'ath Party members from public employment. Order Number 2 dissolved the Iraqi army, putting several hundred thousand trained and armed men out of work with no pensions. Both are published orders, and both were criticised inside the US government at the time. Camp Bucca's role is documented in interviews with former detainees and US personnel: Abu Bakr al-Baghdadi was held there in 2004, and a significant part of the later ISIS command structure was made up of former Iraqi military officers who met in US detention.
03What's known
When Mosul fell in June 2014, ISIS captured large quantities of US-supplied Iraqi army equipment - Humvees, artillery, small arms, some armour - because those stocks had been transferred to the Iraqi state, whose divisions collapsed. That is how most "American weapons in ISIS hands" photographs are explained. The honest formulation is the one the Iraq inquiries and the US military's own after-action studies reach: this was a documented consequence of the invasion and its immediate decisions, not a documented intention.
Documented risk
The invasion did not create ISIS as policy, but the record shows it removed every structure that would have contained it and supplied the grievance, the trained officers and much of the equipment.