The Inside Track with Jonathan Freedland plus Kevin Maguire [1], Martin Bright [3], Peter Wilby [4] plus Tara Hamilton-Miller [5]

It's only an academic question, but it has suddenly acquired more force, now that he's about to become prime minister. Could Gordon Brown have stopped the Iraq war?

Say Brown had joined Robin Cook in resigning on principle in March 2003. Tony Blair would have had only two options: to quit or to back down to save his government. He would have had to phone George W Bush and tell him that British troops would not, after all, be joining the US military in Operation Iraqi Freedom. We know from all the insider accounts that Bush was determined not to go to war alone. Indeed, he was prepared to go to inordinate lengths to keep his British ally on board. The president could not allow his war to seem like an act of American caprice, rather than the action of the international community. Bush would have had to delay the invasion, thereby giving the UN arms inspectors more time - perhaps enough to discover that Saddam Hussein had no weapons of mass destruction after all. The chain of logic is clear. No Brown, no Britain. No Britain, no war.

Brown never did take that decisive step. He kept well out of what was the defining battle of the Blair years, declaring his view only during the 2005 general election campaign when asked point-blank if he would have handled Iraq the same way as Blair. "Yes," Brown said - and said no more.

From now on, enigmatic distance from key foreign policy issues will not be an option. Brown will have to lead and decide. There can be no delegation of international affairs, the way Blair delegated the economy to his Chancellor. Foreign policy is close to the essence of the prime minister's role. And, as predecessors from Churchill through Eden to Thatcher would surely testify, it's what can make or break you.

Brown will arrive at No 10 with only the sketchiest record in foreign affairs. That is partly thanks to the division of labour entailed by the Granita accord: Gordon got domestic, Tony got the rest of the world. If that was the bargain, Brown stuck to it faithfully, never once cutting across Blair's international turf. That's the charitable reading. Brown's critics have a harsher gloss. For them, his silence on Iraq was motivated by his Macavity-like habit, identified by the former mandarin Lord Turnbull, of vanishing at the first sign of trouble. Either way, Brown's experience in the diplomatic arena is thin. One über-Blairite warns that, when the first international crisis strikes, Brown is not going to know what has hit him. "If Iran invades southern Iraq, you can't commission Derek Wanless to do an 18-month review. You have to decide what to do now. Today."

And foreign policy is notoriously unpredictable. It is often barely a policy at all, less a predetermined strategy than a series of reactions to unforeseen events. After all, who knew in 1997 that Blair would emerge as a muscular neoconservative? Brown could end up surprising us just as much.

It is not only outsiders who are in the dark about his intentions. I asked one pro-Brown cabinet minister what his new boss planned to do internationally and received a candid reply: "I don't know." Incredibly, the man who will be prime minister next month has no full-time foreign policy adviser.

So we're left looking for clues, in his speeches and in his past record. One conclusion emerges straight away: when Brown looks for a way into an international problem, he heads for the door marked "Economics". The most obvious example is the Israel-Palestine conflict. In 2005, Brown deployed his trusted lieutenant Ed Balls, along with a Treasury official, Jon Cunliffe - whom some tip to move over to No 10 to advise on foreign affairs - to study, on behalf of the G8, prospects for "supporting the Middle East peace process through economic development". The idea was to replicate for Israelis and Palestinians what had worked so well in Northern Ireland: ensuring a flow of investment and jobs into a former war zone, giving the next generation a stake in peace. If today an 18-year-old Catholic lad in Belfast would rather get a job in some plush corporate HQ than become an IRA volunteer, why couldn't the same be true of young Palestinians of the future, choosing a career with an internet start-up over "martyrdom" with Hamas?

Something to lose

It's not just the Middle East conflict: ask Brown about Afghanistan, and his first answer is that the Afghans need an alternative crop to the poppy. He speaks about the need for investment in Iraq, too. Peace will hold, he believes, when people have something financial to lose. This economist's approach to foreign affairs might just be a function of Brown's CV: until now, economics was the only way he was allowed on to the world stage without treading on Blair's toes. But it goes deeper than that, revealing something of what Brown genuinely believes. There are flaws in the approach, to be sure. On Israel-Palestine, it's clear that investment will be vital after the two sides have signed a peace agreement. But the politics surely has to come first (just as investment in Ulster could come only after a meaningful ceasefire). To talk about industrial parks and apprenticeships now, while Hamas is firing rockets at Israel, Israel is shelling Gaza, and Fatah and Hamas are killing each other, risks looking idealistic, if not irrelevant.

There are other important pointers. Brown's championing of help for the developing world is well known, from his leading role in the campaign to cut debt to his invention of the International Finance Facility, designed to increase development aid with money from the bond markets. In both cases, Brown chivvied other governments to do their bit, even bringing a Republican US Treasury secretary, John Snow, on board for debt relief. That could be a precedent, a sign that coalition-building is not beyond him. It has also won him a strong reputation among NGOs and church groups.

What does this belief in development aid, typified by his tripling of the Department for International Development's budget, tell us about Brown? Admirers say it demonstrates his core belief that poverty is a scourge that governments have to tackle, at home and abroad. This, they say, is the legacy of his upbringing in the manse, the tangible evidence of his sotto voce brand of Christian socialism. Yet it would be a mistake to read Brown's belief in development as entirely abstract and ethical. Rather, it illuminates what might be a funda mentally different approach to the hard-headed, real-world questions thrown up by the "war on terror" - fundamentally different, that is, from the policy pursued by Blair.

If expressed in a soundbite, this would be "tough on terrorism, tough on the causes of terrorism". Brown is too canny to say anything that could be understood as justifying terrorist murder, but privately he argues that there are conditions in which violent extremism can flourish. These include states that break down through desperate poverty and disease.

Blair hangover

Of course, that doesn't explain the 19 hijackers of 9/11, most of them from comfortable Saudi backgrounds. But Brown is looking ahead to the failing states of Africa, worried that they could fall prey to al-Qaeda. In a speech in April to Labour Friends of Israel, he spoke at length about finding partners in Africa. His belief is that helping those countries - say, by funding education for those 120 million of the world's children who don't go to school - is both a moral good in itself and pragmatically smart, preventing jihadism winning more recruits. Brown talks often of the postwar Marshall Plan, which spent US money on European and other countries, in part to prevent them falling into the pro-Soviet column. He may well see aid to Africa the same way, with jihadism the new global menace to be defeated.

As for Iraq itself, a move is expected early, if only to draw a line under the hangover of the Blair era. The likeliest would be an accelerated troop withdrawal. But Brown would be wary of spinning that as a repudiation of Blair's war: after all, he knows that we know that he voted for it, and saw the raw anger for himself as an anti-war heckler was ejected from a hustings meeting he addressed on 20 May.

What's more, Brown still privately defends the decision to invade. He argues the case not on the grounds of weapons of mass destruction or Saddam being a vile dictator, but that Iraq's serial defiance of repeated UN resolutions could not go unpunished. Critics of the war will say that Saddam could hardly have been defying UN resolutions when, as we now know for sure, he had indeed disarmed.

Brown might want to couple any withdrawal from Iraq with another gesture, perhaps in the opposite direction. He might, for example, boost the British presence in Afghan istan, as if to allay any fears in Washington that Britain under him was going soft. But any desire to prove his hard power credentials is unlikely to include signing up for a military solution to one of the most pressing questions waiting for him in the Downing Street in-tray: Iran's apparent desire to acquire nuclear weapons. On 13 May, Brown said he did not anticipate any attack on Iran, because the process of multilateral engagement and negotiation is working. Indeed, he even spoke of a "new multilateralism", in which disputes will increasingly be settled through international institutions and dialogue. It may be too hopeful, but it suggests at least a different starting point from Blair, who sent British troops into combat five times in his first six years.

Then comes the crucial relationship, the one with the US. Of all Brown's diplomatic moves, this is the one that will be watched most intensely. There won't be the love-in that Blair struck up with Bush, if only because Brown knows how dearly that cost his predecessor, but it might be more complex than some hope. Brown is a known Americanophile - much more than was the French-speaking, Tuscany-visiting Blair. He reads American books and, famously, used to holiday annually in Cape Cod. His friendships range from Ted Kennedy to Alan Greenspan, the former head of the Federal Reserve. Brown will certainly be able to do business in Washington.

Aberrational fantasies

Brown also has the equipment to be more discerning than Blair ever was. Blair was powered by an undifferentiated belief that he had to be close to the White House, whoever was in it, whatever they did. Brown will be better able to distinguish enduring American interests from aberrational, neoconservative fantasies, siding with the US for the former and keeping his distance from the latter. He will be an enthusiastic, loyal ally of the US - but his support will not be unconditional. And if, once Bush goes in January 2009, the president is replaced by a Democrat, from the party with which Brown has good, personal links, so much the better.

On Europe, we have had several glimpses of the shape of things to come. Brown's impatience at finance ministers' meetings, and his derailment of British membership of the euro, suggest a sceptic. He loathes the Common Agricultural Policy, a piece of protectionism that cannot be defended in an era of global free trade. With the French and the Germans now talking of resuscitating the corpse of an EU constitution, reclothing it as a treaty, a collision seems likely. Brown would not want to rouse the ire of the Eurosceptic press by driving such a treaty through parliament; but nor could he risk submitting it to a referendum that he could lose. Expect some trademark footwork to get this booted into the long grass.

Where Brown would like to set a lead, rather than just react, is on the aid and trade agenda he has made his own (his only beef with the Make Poverty History campaign is that he thinks it should be pushing governments, including his, harder), and also on climate change. He wants to outman oeuvre the Tories on this territory not by matching David Cameron wind turbine for wind turbine, but by coming up with the kind of large-scale breakthrough that would make Cameron look like a lightweight. He speaks of plans for the reforestation of the Congo, of recasting the beleaguered World Bank as a new Environment Bank, of establishing a carbon market in London. This is the level he wants to operate on; he'll leave the organic broccoli to Cameron.

These, then, are the instincts that should steer Gordon Brown when he enters the international arena as leader of what is still one of the world's most powerful nations. How much will they determine what he does in office? The lesson of recent history is that they may be no guide at all. As Tony Blair discovered one September morning in 2001, everything can change when a single event comes out of a clear blue sky.

Jonathan Freedland writes for the Guardian