To Iran, the United States is still, officially speaking, the Great Satan. From the U.S. perspective, Iran is one of the two remaining members of what President Bush famously termed an axis of evil. However, Iran sent a delegation to Iraq to try mediate an end to the standoff between radical Shi'ite Muslim cleric Moqtada al-Sadr and the U.S. occupation authority. The United States made no move to stop the effort.

An Iranian diplomat was gunned down in Baghdad during the visit and the mediation subsequently broke down. Nevertheless, analysts said the Iranian effort in Iraq was symptomatic of a broader political struggle in Iran for influence, power, and international legitimacy.

Just how much clout Iran has in Iraq and just who in Iran wields it is murky.

Juan Cole, a professor of Middle East and South Asian history at the University of Michigan, said the Iranian mission to Iraq is part of an effort by President Mohammad Ali Khatami and his fellow reformists to regain some influence they had lost to the hardliners. President Khatami has pointedly distanced himself from Mr. al-Sadr.

"That faction has been under enormous pressure inside Iran," Mr. Cole said. "Of course, it was sidelined in the recent elections by the hardliners. So reaching out and playing this kind of positive role in the region may be one way for the reformists to break back out of their isolation."

Michael Rubin, who was until last month a political advisor to the Coalition Provisional Authority in Baghdad, said the Iranian role in Iraq was anything but positive. He added that Iran is meddling and trying to set up its own cells in Iraq. "I think having Iranian involvement in Iraq is like having the arsonist volunteering to put out the fire," he said.

Moqtada al-Sadr, the cleric turned insurgent, is believed to have strong backing from the hardline elements in Iran. His mentor, according to analysts, is Ayatollah Kazem al-Husseini al-Hairi, a senior Shi'ite cleric in the Iranian holy city of Qom. How much influence he actually exerts on Mr. al-Sadr is not clear. While supreme leader Ayatollah Ali Khamenei has welcomed the forced departure of Saddam Hussein, who led a bloody decade-long war against Iran, he has sharply condemned the U.S.-led occupation of Iraq.

Mr. Rubin said that Iran is actively helping Mr. al-Sadr's forces.

"The Iranians have been funding some of the radicals with arms, with Revolutionary Guards," he added. "The Iranian charge d'affaires in Baghdad is actually not a diplomat. He is a member of the Qods force, which is the unit of the Revolutionary Guards dedicated to the export of the Islamic revolution. The last thing Iraqis want is for us to involve non-Iraqis in this matter."

However, Professor Cole said that Iran's role in Iraq is not as pervasive as Mr. Rubin and like-minded analysts portray.

"There are persistent reports that Iran has, and the hardliners in Iran have, provided material support to Moqtada and his faction," he said. "I personally think those reports are overblown. I think this is largely an indigenous Iraqi movement, but it may have gotten some money. Lots of Iraqi groups have gotten money from Iran, including some of the more secular politicians."