Several council ambassadors said they hope the dialogue that produced the resolution signaled a new commitment to multilateralism.
UN Secretary-General Kofi Annan said the episode showed that the United States needed the "unique legitimacy" of the United Nations to help create a credible interim government in Iraq.
A little more than a year ago, the council was sidelined by the Iraq war and challenged by U.S. officials for its relevancy. The unanimous vote appeared to mark a UN revival of sorts.
But experts on the UN say there was little doubt all along that the council would decide on the postwar arrangements for Iraq. It was also clear, they say, that Washington would make sure to gain UN support for the political transition.
In some ways this recalls the council's role in Kosovo. The council did not authorize the NATO air campaign yet it created the UN mandate that still runs the province.
The Iraq resolution did not mark any shift in positions about the war, nor did it trigger any new commitment of military forces. But it might have helped repair relations between the permanent five veto-wielding members who engaged in rare public clashes over Iraq, says David Malone, president of the International Peace Academy.
"Iraq has undermined the role of the UN as well as the prestige of the United States internationally,” Malone says. “There have been no winners on Iraq. It's not as if Russia and France have done fantastically well out of Iraq. They haven't. So, all parties are bruised as a result of Iraq."
Two previous UN resolutions -- also unanimous -- authorized the occupation of Iraq and called for a vital UN role in the country's reconstruction. Russia, France, and Germany have stressed after each resolution their refusal to commit peacekeeping troops.
Max Boot is a senior fellow on national security studies at the Council on Foreign Relations, an independent policy institute. He tells RFE/RL that it is too early to say whether the latest resolution is meaningful.
"This is the third unanimous Security Council resolution since the invasion of Iraq [in 2003]. The first two didn't produce much by way of action. I think it remains to be seen what the effect of this one will be. It's certainly good that it was unanimous, it's good that it was passed, but we shouldn't necessarily assume that this will miraculously transform the attitudes of member states or change reality on the ground in Iraq," Boot says.
But council members stress that despite their differences over Iraq, they have remained engaged on a variety of issues. Since the invasion of Iraq, the council has widely expanded peacekeeping operations, particularly in Africa.
In that time, the United States has also worked closely with China to advance talks on North Korea; it has coordinated with Russia and France to strengthen counter-terror and non-proliferation measures; and it is engaged with Germany in peacekeeping in Afghanistan.
France's UN ambassador, Jean-Marc de La Sabliere, commented on the broader cooperation.
"On Iraq, we [now] agree. But let's not forget on all other matters we have worked even during the Iraqi crisis very well between France and the United States. For example, the resolution on non-proliferation was possible because of a very good cooperation between some delegations and, in particular, France and the United States and the U.K.," de La Sabliere said.
France, Britain, and the United States are also working together to pressure Iran to comply with an investigation into its nuclear program by the International Atomic Energy Agency (IAEA). So far, the diplomacy has been confined to Vienna, where Iran has faced repeated criticism by IAEA members.
But the issue could be referred to the Security Council, which has the power to authorize sanctions or even military action if necessary. Boot says the Security Council's relevancy could again be called into question.
"I think one key test will be the case of Iran, which seems to be violating an agreement on limiting its nuclear production and has been called out by the International Atomic Energy Agency and the question is what, if anything, the UN Security Council will do to uphold the non-proliferation treaty and the authority of the IAEA," Boot says. "I think that's going to be a big test."
The architects of the UN Charter and Security Council attempted to impose binding international law on the use of force. Some international law scholars say the wars in Kosovo and Iraq highlighted the flaws in the model. But others say for all its difficulties, the Security Council is working according to the design of UN founders.
Michael Doyle is an expert on international affairs who teaches at Columbia University in New York. He tells RFE/RL that states that defy the council risk losing the banner of international legality because the council claims a monopoly on the use of force other than in self-defense.
"That contradiction was built in from the very beginning. It should be a signal to a state when they can't get a consensus that their diplomacy has to move very carefully," Doyle says.
Doyle served as a UN assistant secretary-general in the period prior to the Iraq invasion. He believes the Iraq experience has shown the United States the value of consensus on the Security Council in terms of the claim on international legitimacy.
"It's worth the diplomatic effort and the U.S. eventually came back to that view, especially as it experienced difficulties in Iraq and saw that the Council's support could help make the transition somewhat smoother," Doyle says.
So far Resolution 1546, which will formally end the U.S.-led occupation on 30 June, has not coincided with a slowdown in violence in Iraq. Car bombs yesterday killed more than 40 people, prompting Annan to reassert that circumstances do not permit a return of UN staff to Iraq to aid in the transition.