If this war with Iraq is to be a moral war, it must be fought in a moral way

Of course, war cannot be sanitised, and all bombs have horrible effects. But even in war there are basic rules

Those of us who support the coming war must be honest about the damage it will cause. Horrifying numbers of people will die – the estimate from US intelligence and international aid groups is 10,000 to 100,000 Iraqi military deaths, with civilian casualties put at 1,000 to 10,000. I firmly believe that even this is better than leaving Saddam in power, but every conceivable move must be made to minimise the damage. Tony Blair has made a crucial contribution to the Americans' move to overthrow the dictator, and he is entitled to ask for some substantial measures in return. So what should he be saying to the Pentagon?

The first important demand – that the Americans should travel as far down the UN route as possible – has been consistently and bravely made by Mr Blair. Washington reporters with impeccable links to the White House have explained that the huge push by the US for a second UN resolution is being made because of his arguments. The Prime Minister is only too aware of the dangers to the world if the UN ends up being part of the collateral damage in this conflict; the UN played a key role in preventing a nuclear exchange between the US and the Soviet Union in 1962, and may well do so again between India and Pakistan. Its collapse into an impotent League of Nations would be a disaster.

There are many figures around George Bush, such as Vice-President Dick Cheney, who see the UN as an illegitimate, clumsy bureaucracy that can only act as a brake on American hegemony. They would be perfectly happy to see it capsize; remember, the Senate Foreign Relations Committee blocked moves to pay US dues to the UN only a few years ago, and there was deadlock until the billionaire Ted Turner stepped in to pay them instead. Because of Mr Blair (and Colin Powell), this view has not prevailed so far.

Yet the UN must be a way of dealing with the problem of Saddam's tyranny and his weapons, not avoiding it. The UN is a pluralistic body with conflicting institutions and actors within it. If the clear UN resolutions threatening "serious consequences" for Saddam are not upheld by the Security Council, then a coalition of the willing will have to proceed. At least Britain and the US will have tried to make the UN effective and to preserve the international architecture created after the Second World War. Mr Blair may yet make it work.

The other key demand Mr Blair is pressing is that post-war Iraq must be a democracy. The Bush administration is divided on this. There are passionate advocates for rebuilding Iraq as a model government for the Middle East. Paul Wolfowitz, the Deputy Secretary of Defence, is the most eloquent, and President Bush's key speech on this topic last week seemed to reflect his thinking. This approach would, however, require Mr Bush to renounce the platform on which he ran for the presidency, which was specifically against nation-building, or "sending the army to do social work". Mr Blair could be a crucial figure in tipping the balance towards those who support Iraqi democracy.

But there are other problems with the war which the British government is not yet working as hard as it could to minimise. Two of the Government's allies – Israel and Turkey – have the potential to exploit the conflict for terrible ends. Tom Segev, one of the best-connected and most astute journalists in Israel, was in London this week, and he is seriously worried that Ariel Sharon "might use this war as an excuse to expel some Palestinians from the Occupied Territories." This idea of "transfer" (a euphemism for ethnic cleansing) has now become sayable in Israeli public discourse for the first time since 1948. "It's something you used to read about only on the walls of public toilets," Segev explains. "Now we have cabinet ministers who support it," along with – according to opinion polls – 30 per cent of the Israeli population. The far-right National Union Party, now in the governing coalition, expounds this racist idea, which is most commonly boiled down to the phrase "Arabs Out!".

The implications for Middle East peace and for the creation of a Palestinian state would be catastrophic. It would damage US hopes of effecting democratic change in the region for a generation. I am reassured by people in Downing Street that the Americans know this and are making it clear to Sharon that "transfer" would be totally unacceptable – but I must confess that I am doubtful that the Bush administration has the will to make its massive financial handouts to Israel contingent on submitting to these demands. They have not even restrained the construction of illegal settlements on Palestinian lands, despite Mr Bush's public call last week for this to be done. Mr Blair has, in fact, been calling for the US to go much further and to publish a US "road map" for peace that includes a viable Palestinian state – but to no avail.

Similarly, the Turks could use the war as a pretext for seizing northern Iraq, which has effectively operated as an impressively democratic statelet for the last decade. This would be just as unacceptable as the expulsion of Palestinians. The Turks have a disgusting record of abusing Kurds, and the deployment of Turkish soldiers into de facto Kurdistan would be rightly and violently resisted. At the very most, the presence of Turkish soldiers must be limited to a very brief period (long enough for Turkey to be reassured that its borders aren't threatened). Worryingly, the British Government is not yet pressing for this. Hopefully, Turkey's uncertainty about joining the war will mean that it gets no rights at all over Kurdish territory for even a minute. But however this plays out, the Kurds – who have been one of the great causes of the left for centuries – must not be forgotten.

There is one final – and lethal – problem. I passionately believe in the justice of freeing the Iraqi people from Saddam, and it is heartening that Mr Blair now uses this as one of the main justifications for the war. Yet there is a danger that the use of cluster bombs and depleted uranium munitions will puncture all his talk of humanitarian action. Of course, war cannot be sanitised, and all bombs have a horrible effect. But even in war there are basic rules. Most nations now agree that forbidding cluster bombs should be one of them. They are effectively land-mines dropped from the air, and they are still killing civilians in Kuwait over a decade after the last Gulf War. To drop them now will be to kill Iraqis for many years to come.

The US is one of the only countries that still insists on using these immoral weapons, in the name of "maximum military flexibility". There is no need for them; they are imprecise and maximise the death of civilians. Similarly, there is too much risk that depleted uranium may cause cancer (the scientists offer a mixed verdict) to justify using it. Human Rights Watch has launched a campaign for precisely this purpose: not to stop the war, but to make sure the war does as little damage as possible to the civilian population of Iraq. (Its website, www.hrw.org, provides important information about how we can exert pressure to make this happen.)

Mr Blair is plainly sincere when he talks about this as "a moral war" – and, even without the caveats, the war would probably still, on balance, be better than leaving Saddam to butcher his own people and develop horrifying weapons. But the PM is still in a position to make this a far, far more moral war.

johann@johannhari.com