Though he holds no official title in the Iraqi government, this Iranian-backed cleric is one of his country's most influential political and religious leaders. To many Iraqis, he is a symbol of resistance to occupation. Once one of America's "most wanted" militants, he was crucial in helping to form the government of national unity last December, after months of wrangling. His return to Iraq on 5 January 2011 - since 2007, he has been in self-imposed exile in Iran - raised questions about his intentions in the lead-up to the withdrawal of US forces. Thousands turned out to hear his speech, in which he described the US, Israel and the UK as "common enemies". It remains uncertain whether he will seek a formal role in the new Iraq.
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