Questions are raised over what the Iraq’s fragile new national unity government is capable of achieving. British aides admitted there was no short-term prospect of stopping the sectarian murders plaguing the country.

Iraq’s prime minister, Nuri al-Maliki, vowed to use “maximum force against terrorism”. But his government was met with a fresh wave of bombings, killing at least 19 people in Baghdad alone. British officials are aware that the new government, due to internal sectarian disputes, has been unable to fill the key interior and defence posts. The US ambassador to Baghdad added to the sense of foreboding by predicting that the next six months would be “critical’’ for Iraq. To achieve stability, the government must “get the security ministries to transform in such a way that they will have the confidence of the people”, Zalmay Khalilzad said.

Blair, after making his own soundings with the Iraq government, will fly to Washington to call for a sweeping strengthening of international institutions such as the UN. But aides have forecast no rapid reduction in the British troop presence in Iraq. There remain substantial doubts about whether the US and British troops can avoid the country spilling into a de facto partition state, with Kurds in the north, the Sunnis in the centre and Shia Muslims in the south. British sources acknowledge that the rise of sectarianism and the militia forces has meant that the Iraqi security forces are nowhere near the integrated force they were intended to be by now.

The US secretary of state, Condoleezza Rice, said top American military commanders would meet with the Iraqi government in the next few weeks. She said the US and Iraqi generals “will come up with plans that include what remains to be done, what role Iraqi forces can play in that, what role coalition forces still need to play”.

Neither President Bush nor PM Blair, both suffering plunges in personal popularity, will accept that the country has descended into civil war, or that the coalition troop presence is deepening the crisis, leaving them with few options. But Blair will find when he reaches US that there is a growing mood among US Democrats for a withdrawal 18 months from now.

At best, Britain is looking at a withdrawal from some provinces, in what the new foreign secretary, Margaret Beckett, has described as “a case-by-case basis’’ in provinces and cities. She said there was no question of “cutting and running”, and that the troops would remain as long as they were needed to assist Iraq in maintaining security. Setting a predetermined date for withdrawal would act as a magnet for terrorists, the government insists.

Bush nevertheless said Iraq’s new government marked a “new day for the millions of Iraqis who want to live in freedom”. He promised that “the United States will continue to assist the Iraqis in the formation of a free country, because I fully understand that a free Iraq will be an important ally in the war on terror, will serve as a devastating defeat for the terrorists and Al Qaeda, and will serve as an example for others in the region who desire to be free”. Briefing reporters after the cabinet met in Baghdad, Maliki said his government would hold out the offer of dialogue to insurgents who laid down their weapons. He vowed to reimpose the state’s monopoly on the armed forces, and crack down on militias.

He said he hoped US forces could start to withdraw on an objective timetable. But Maliki’s national government will have as one of its first, and possibly impossible, tasks to review a constitution that Sunnis say gives the Shia and Kurds too much control over Iraq’s vast oil resources, and eventually will split the country as the Kurds take control of new resources. The government has only four months to review the constitution. The US ambassador, Khalilzad, the key player in Baghdad in trying to get agreement over the past few months on the composition of the government, sounded more optimistic that coalition troops could be withdrawn.

Apart from meeting Bush for the first time since Blair was re-elected last May, the prime minister will make the last of his three big speeches on foreign policy, focusing on the need for new international institutions to meet a newly globalised world facing further challenges to world security.

Blair has been advocating for most of his premiership an active interventionist diplomacy through the UN Security Council, using diplomatic, legal or humanitarian means, or, exceptionally and as a last resort, by force. He believes that the UN secretary general needs more authority and flexibility to manage his staff and resources; and in turn should be more accountable to the UN’s member states in that work.

Britain has long supported the expansion of both the permanent and non-permanent membership of the Security Council, arguing for permanent representation for Japan, Germany, India and Brazil, and for Africa. — The Guardian