If it has accomplished anything it has bolstered Iran's influence in the region.
...and the recent Arab summit hosted in Sudan is evident of this reality where nations voiced their opinions on Iran's influx of power.
Iran's has increasingly developed closeness with the majority shia population of Iraq. Iraqi leaders like Jaffari, Al-Hakim and Sistani all have close ties with Iran.
The Bush administration noticed this even before the recent Arab summit when our ambassador to Iraq, some reports say wrote a letter to Iran asking them for dialogue over Iraq.
Iran has clearly scored major points in the region and all thanks to the invasion.