For a slightly more detailed summary that also sees Iran as emerging the real victor of the Battle of Basra, see this piece from Radio Free Europe. Key details include the following:
Iran is sufficiently powerful to get the two most important religious parties in Iraq, the Sadrists and al-Hakim's Supreme Islamic Council,
to Iran to broker a ceasefire organized by Iran.
Several sources indicated as early as March 28 that a representative of al-Maliki's Al-Da'wah Party, Ali Adib, and Hadi al-Amiri, the head of the Badr Organization, the military wing of the Islamic Supreme Council of Iraq (ISCI), traveled to the Iranian city of Qom to meet with Iranian officials.
According to McClatchy Newspapers, the aim of the trip was twofold:
to press al-Sadr to restrain his militia and to call on Iran's Qods Force to stop supplying weapons to Shi'ite fighters in Iraq. It was also revealed that the two men went to Iran without consulting with the prime minister.
Haidar al-Abadi, a member of Al-Da'wah, said that the delegation was from the Shi'ite-led United Iraqi Alliance, which is dominated by Al-Da'wah and the ISCI, "and the prime minister was only informed. It was a political maneuver by us."
This quiet Iranian diplomatic initiative differs dramatically from Ahmadinejad's strident rhetoric. The media has focused on the significance of the Basra events for Iraq; what are the implications for Iran? Will Iranian elites derive the lesson that diplomatic peacemaking might be a more effective way of making Iran a major regional player than a war of words with excitable opponents? What will be the impact on Iranian politics of quiet peacemaking led by the commander of the al Quds Brigade, as opposed to, say, a diplomat or moderate politician? What will be the impact on regional attitudes toward Iran?
Only time will tell how political realignments will play out: the various impacts of the battle of Basra are by no means inevitable or straightforward. Keeping in mind a complex adaptive systems perspective on these events may help in understanding them. Such a perspective underscores that actors (individuals, factions, countries) are adaptive agents in an interactive system in which each actor influences and adapts to the others. Depending on what follows, the battle of Basra may have a long-lasting and far-reaching impact on regional politics.