By Roger Hardy
Middle East analyst, BBC News
Iraqi politicians are discussing the formation of a new alliance designed to isolate the radical young Shia cleric Moqtada Sadr.
Shia cleric Moqtada Sadr is a key figure
The alliance would bring together some of the main Shia, Kurdish and Sunni groups, but the party of Prime Minister Nouri Maliki has not decided whether to join.
One of the central, and most difficult, questions in Iraqi politics is what to do about Moqtada Sadr and his powerful militia, the Mehdi Army.
Sunni Arabs accuse the militia of carrying out sectarian attacks, and the Americans have long been pressing Prime Minister Maliki to dismantle it.
Some of the main political parties are now so worried about Moqtada Sadr's growing influence that they are trying to put together a new alliance designed to weaken and marginalise him.
This would bring together the two main Kurdish groups, one of the main Shia parties - the Supreme Council for the Islamic Revolution in Iraq, or Sciri - and the Sunni Islamist party led by the country's vice-president, Tariq al-Hashimi.
But Mr Maliki and his Shia party, Daawa, are undecided about whether to join.
The prime minister is politically dependent on Mr Sadr's support, and some members of his party favour keeping him inside the political tent - rather than provoking him by trying to push him out.
Mr Maliki may be worried that his political rivals, perhaps with quiet support from Washington, want to force him from office.
Last week President George W Bush met one of the key members of the proposed new alliance, the Sciri leader, Abdel Aziz al-Hakim.
Later on Tuesday, he plays host to Mr Hashimi.