Much of the money for rebuilding Iraq has already been spent, and Iraqi soldiers are gradually taking over for their American counterparts. So what can the United States still use as leverage? It may be that the strongest influence is the simple fear of what would happen if the US up and left.
"Most of Iraq's leaders recognize that if the US were to pull out precipitously, things could get much worse," says Phebe Marr, an Iraq expert at the US Institute of Peace who has spent considerable time with Iraq's principal political factions. "All the talk about the US getting out, an exit strategy and so forth, has them worried. It's having an impact."
Yet even as the US shows signs of growing increasingly impatient with Iraqi leaders over their inability to name a new government, that doesn't mean the US wants to look as if it is determining Iraq's future. The result is a delicate balancing act: It's applying pressure for political action even while encouraging a sovereign Iraq that appears to stand on its own two feet.
For weeks, the US has left its behind-closed-doors arm-twisting to its ambassador in Baghdad, Zalmay Khalilzad, with the aim of seeing a national unity government named that is acceptable to the major political factions and population groups. But with alarm growing that what the US calls a "power vacuum" is feeding sectarian violence, the pressure has become more public - and from higher up.
On Tuesday, President Bush said, "It's time for the elected leaders to stand up and do their job." The remark came one day after Secretary of State Condoleezza Rice concluded a visit to Baghdad accompanied by British Foreign Secretary Jack Straw.
The two diplomats gave no public indications of their preference for prime minister, the keystone in the construction of Iraq's first permanent government since the fall of Saddam Hussein. But the US has made little effort to squelch speculation that it wishes to see Prime Minister Ibrahim al-Jaafari give up his battle to retain his post.
Ms. Rice and Mr. Straw met once with Mr. Jaafari in a tense photo session, but pointedly met for meetings and a breakfast with two other prominent Shiite leaders, Vice President Adel Abdul Mahdi and Abdul Aziz al-Hakim, who heads one of Iraq's major Shiite parties. Mr. Mahdi lost his bid to be nominated prime minister by only one vote in secret balloting of the Shiite bloc.
Those meetings may have only served to spotlight the deepening fissures within Iraq's Shiite majority - a latent situation that could lead to a new front of violence. That is especially true, some analysts say, because Jaafari has the backing of the volatile young cleric Moqtada al-Sadr. Mr. Sadr has recently toned down his anti- occupation rhetoric as he has amassed power in the new National Assembly, some observers note, but might reignite resistance if he decided it might enhance his kingmaker role.
In addition to the two diplomats, members of the US Congress have also visited Baghdad and key political leaders recently. Some have told Iraqi counterparts that the US commitment to Iraq is under pressure and could be scaled back if they do not end their political infighting.
Yet the US is also operating with the knowledge that too much pressure could have the negative result of prolonging the leadership stalemate among politicians who are sensitive about foreign influences in Iraq. "There are misgivings and growing mistrust towards those [leaders] with too-close ties to outsiders, particularly the US and Iran," says Ellen Laipson, a former CIA official with foreign-policy and national-security expertise.
By its investment and presence in the country, the US has a right to exercise pressure, and there are things it can do "without going over the line," says Ms. Laipson, now president of the Stimson Center, a Washington defense and security think tank. "We are operating within a boundary that says it's not up to us to pick the names" of who will govern, but that says the US provides "broad guidelines on what will help the security situation and get them on the right track."
So the US is in "the unusual situation of saying we'd like someone other than Jaafari" for prime minister, she says. But the US is also emphasizing that the ministers of defense and interior should be someone with no ties to the country's powerful and ethnically based militias.
Still, with US clout waning, other means of pressuring Iraq's leadership are under discussion. One idea is an international conference that would be held outside Iraq - something similar to the Bonn conference that provided guideposts to Afghanistan's post-Taliban government.
Ambassador Khalilzad, an Afghan-American who was previously ambassador to his native country, has floated that idea. Yet while "internationalizing" Iraq could help, some experts say, they also doubt that many countries wish to step in to help Iraq. Add to that the deep suspicions that Iraqis harbor toward the neighboring countries that might have some influence.
In any case, many experts caution that naming a government is not going to magically transform Iraq, any more than earlier milestones - such as elections - have done the trick.
"It's a little misplaced to say that [forming a government] somehow solves the sectarian problem or any of the other really difficult challenges on the ground," Ms. Marr says. "It will probably help some to have a new government, but we shouldn't be under any illusions that the day after, the insurgency will put down its guns, or the sectarian violence is going to stop."