The religious landscape of Iraq is complex and somewhat enigmatic to the western world. Nearly 97% of Iraq's 25 million people are Muslim, and a majority of Iraqis are Shiite rather than Sunni. What does that mean? And how powerful is the prominent cleric Ayatollah Ali al Sistani who has effectively challenged the American-led coalition. Could he become another Islamic revolutionary like Iran's Ayatollah Khomeini?

As part of Iraq's rebuilding process, the Iraqi governing council agreed on an interim constitution that cites Islam as a source — but not the primary source — of future legislation. Approval of the interim constitution was delayed first by violence, and then by a group of Shiite council members who raised objections to elements within it. Host Krista Tippett speaks at length with Iraqi-American professor and advisor, Ahmed al-Rahim, for insight into the unfolding new relationship between mosque and state in Iraq.