Inside Story - Iraq's political wrangling

Iyad Allawi, the former Iraqi prime minister whose Iraqiya coalition won 91 seats in the country's March parliamentary election, has sought support to form a government from Moqtada al-Sadr, the Iranian-backed Iraqi Shia leader. What would it take for Allawi and al-Sadr to form a political alliance? And to what extent are outside forces hindering or aiding the process?