Over the last few days, the sense of exuberance among the Iraqi Shia has been palpable.
The Shia's religious rituals were banned under Saddam Hussein
Under Saddam Hussein, many of their public symbols and rituals were banned.
Now long pent-up feelings and long-suppressed political views are tumbling out into the open.
Comprising some 60% of all Iraqis but long ruled by a Sunni elite, the Shia have long felt themselves to be an underclass.
But for all their sense of communal solidarity, they are not homogeneous.
One divide is between the religious and the secular.
Another is between the political activists and those who favour keeping out of politics.
In the second category is Ayatollah Ali Sistani, the most senior religious figure in the Shia holy city of Najaf.
Najaf is still trying to recover from the violent events of 10 April, when a prominent cleric, Abdel-Majid al-Khoei, who had recently returned from exile in London, was killed in circumstances which are still far from clear.
Among the activists, three main trends are apparent:
- The Daawa party
- The Sadr group
The Daawa party
Founded in the 1950s, the Daawa party is the oldest of the Shia Islamist movements.
After a series of attempts to assassinate Saddam Hussein and some of his ministers, it was harshly suppressed and eventually split into several factions.
A senior Daawa figure, Sheikh Mohammed Nasseri, recently returned to southern Iraq from exile in Iran as part of an attempt by the party to re-establish itself after years of clandestine existence.
The Supreme Council for the Islamic Revolution in Iraq is a Tehran-based group, founded in 1982 and headed by Ayatollah Mohammed Baqr al-Hakim.
The ayatollah's brother, Abdel-Aziz, has also recently returned from exile, as Sciri seeks to build up a bigger grass-roots following.
Sciri, like Daawa, boycotted last week's meeting of anti-Saddam Iraqis, organised by the Americans in a big air-conditioned tent near the southern town of Nasiriya.
But Sciri may be finding the Iranian connection a liability rather than an asset. Twenty years ago Iraqi Shia were more excited about the Iranian revolution than they are today, when it has lost much of its fizz.
The Sadr group
This group represents a radical, home-grown trend which some see as a force to be reckoned with. It is named after a popular religious figure, Ayatollah Mohammed Sadeq al-Sadr, who was assassinated - apparently by agents of the Saddam regime - in 1999.
There were angry protests against the alleged arrest of a leading Shia cleric by US troops
The group is now led by the ayatollah's 30-year-old son, Muqtada al-Sadr.
It has a following in Najaf, where some people have implicated it in the killing of Abdel-Majid al-Khoei - a charge it strongly denies.
It is also popular in Baghdad's Shia suburbs, the biggest of which, Saddam City, has now been renamed "Sadr City".
There were protests in Baghdad on Monday after US forces reportedly arrested Sheikh Mohammed al-Fartusi, a cleric belonging to the Sadr group who has emerged as a prominent local leader in Sadr City.
If he was indeed arrested, as his supporters allege, the Americans may have thought better of it. He emerged on Tuesday, to a jubilant reception from his supporters, who claimed US forces had released him.
Spectre of sectarianism
Some Iraqis from the country's Sunni and Christian minorities are uneasy about the new mood of Shia resurgence.
Recent anti-American rallies suggest a radicalisation of the Shia
They fear that, in the new climate, the Shia will demand not just an end to their oppression but a dominant role in the new order.
That would trigger Sunni alarm in Iraq - and among the predominantly Sunni ruling elites in the Arab world.
At root, the question is whether the factors that divide Iraqis will prove stronger than the factors that unite them.
Recent anti-American demonstrations have witnessed the slogans "No Sunni, no Shia - only Islamic unity".
Most Iraqis are indeed united by allegiance to a common faith - and by shared suffering under Saddam's rule.
Intermarriage between Sunni and Shia is commonplace. Both communities share a sense of national pride.
A crucial issue is whether the Shia, or a significant number of them, will press for Iraq's transformation into an Islamic state.
Most Iraqis, and many Shia, seem to favour the separation of religion and state.
But if the Americans mishandle the post-war transition, this could radicalise the Shia and foment unrest - with potentially damaging consequences for both Iraq and the region.