The NIA is basically the old United Iraqi Alliance minus Maliki’s Dawa Party. Prof. Cole writes:
In the provincial elections held last January in Dhi Qar, ISCI, the
Sadrists and the Islamic Virtue Party got altogether about 40 percent of the
vote. The Da'wa got only about 23%. Other provincial tallies are
given here. In most provinces, with the exception of Baghdad and Basra, the
old United Iraqi Alliance did just about twice as well as Da'wa.
If the NIA does as well in provincial elections as the old UIA did in
provincial elections, it will again be the biggest party/coalition in the
national legislature. By the constitution, it would therefore form the next
government, and al-Maliki may at that point regret not having joined.