The subject of 9/11 root causes did not receive due attention in the 9/11 Commission report. Islamism, the radical fusion of religion and politics with jihad at its center, is an obvious root cause. Islamist ideology is centered on reintroduction of a caliphate, an Islamic super-state governed by Islamic Sharia law.
In the post Cold War era, Islamism has been competing with the U.S.-led globalization ideology for world domination. The primary tool for the long-term expanion of Islamism is proselytism of Islam, Saudi Wahhabi Islam in particular. Terrorism is a tactic of asymmetric warfare, a great cost-effective equalizer, causing huge political and economic impact on a short-term basis.
The Islamist terrorist networks flouished and grew exponentially during the Clinton era. The President's lack of resolve to fight terrorism and his turning a blind eye to radical Islam fueled the rise of Osama bin Laden from isolation and obscurity to a planetary hydra-like monster. The track record qualifies Clinton to be characterized as the Neville Chamberlain of the 1990s. His predecessors going back to President Roosevelt in 1945 have also contributed a great deal to empower radical Islam.