MPs who care about UN will give support

Imagine you are a Labour MP with a troubled conscience. You are neither a toadying Blair loyalist, nor an anti-war Left-winger. Like Clare Short and possibly most backbenchers, you want Saddam Hussein stripped of his ability to deploy weapons of mass destruction; but you insist Britain must act through the United Nations. You genuinely want to do the right thing. Should you back the Prime Minister tomorrow or not? Let us tackle this question from first principles. Any legal or quasilegal system depends on its powers of coercion. If a court imposes an injunction, it needs to be sure this will be obeyed. Without the power to punish contempt of court, judges will soon become impotent.

That is precisely the danger that the UN Security Council faces. It has repeatedly told Iraq to re-admit arms inspectors without restriction. Saddam has repeatedly refused. For the sake of the UN's credibility, as well as the need to extinguish any threat from Iraq, the Security Council needs to impose its will on Baghdad. If it fails to do so, the UN risks going the way of the League of Nations, which sank into irrelevance in the Thirties when it failed to block Japanese, German and Italian aggression.

From this it follows that the Security Council must make clear its determination to use its powers of coercion unless the arms inspectors are allowed back into Iraq without restriction. Only in those circumstances is Saddam likely to back down. Last week's events prove the point. The Iraqi leader announced the inspectors could return when he saw momentum building up for a Security Council ultimatum.

So far, his offer does not go far enough. He wants to revive the compromise that constrained the arms inspectors in the mid-Nineties, when the Iraqis could declare sites to be "civilian" or "presidential" and out-of-bounds. This is why Britain and the US want a new Security Council resolution: to insist on unrestricted inspections and sanction force if Baghdad fails to comply.

Many worried Labour MPs might well agree with the argument thus far, but cavil at the next step: the possibility that American and British forces might attack Iraq without UN approval if the Security Council fails to act decisively.

In preparing for tomorrow's debate, the PM has two ways to counter this fear. The first is to point out that the only way to coax the Security Council into doing the right thing on Iraq is to threaten to act independently. After all, the council is comprised not of judges who weigh the evidence objectively, but of ambassadors from 15 different countries, each with its own agenda. Playing hardball with the council works. Had Mr Bush promised not to lay a glove on Iraq without UN approval, the chances of the Security Council acting decisively would have vanished. Saddam would have emerged as victor of the crisis, and the credibility of the UN as the loser.

Mr Blair's second argument, should he wish to be candid, flows from this. Suppose the Security Council still ducks the challenge, despite pressure from the US and Britain. The arms inspectors might still return to Iraq, but they will not be able to determine the full extent of Saddam's arsenal. The Iraqi leader will have won the skirmish. In those circumstances, Mr Bush may well decide to take action. Yes, he would be acting outside international law. However, international law would have broken down. The UN would be a busted flush. Britain and the US would be filling a dangerous vacuum, not usurping the powers of a properlyfunctioning global authority.

This prospect makes our worried Labour MPs queasy. They must hope things do not reach this pass. For now, the most urgent task is to inject backbone into the Security Council . This is what the PM has sought to do. For this reason, despite their misgivings, Labour MPs who care for the future of the UN and the international law will back Mr Blair.