John Prendergast: Bush mistook me for Bono

Like his doppelgänger, John Prendergast is a man on a mission - to save 2 million lives in Darfur. Jane Bussmann pushes past Angelina Jolie and Bill Clinton to catch up with the radical peacekeeper

Chad, January: News cameras film Darfur's refugee children for ABC's prestigious Nightline show in the United States. It's unusually good publicity for an old story. The refugees were bombed out of their villages, but a legal stalemate means the UN can't name the perpetrators. But the media-savvy youngsters have made a banner for viewers: blood-coloured paint rains on stick people as a fat man laughs; his caption, "Omer al-Bashir" - the President of Sudan. For two decades, Bashir's Arab government has sent Arab "Janjaweed" militia to purge the black villages of Darfur, stealing their land and livestock.

Chad, January: News cameras film Darfur's refugee children for ABC's prestigious Nightline show in the United States. It's unusually good publicity for an old story. The refugees were bombed out of their villages, but a legal stalemate means the UN can't name the perpetrators. But the media-savvy youngsters have made a banner for viewers: blood-coloured paint rains on stick people as a fat man laughs; his caption, "Omer al-Bashir" - the President of Sudan. For two decades, Bashir's Arab government has sent Arab "Janjaweed" militia to purge the black villages of Darfur, stealing their land and livestock.

In 2003, black rebel groups took up arms. The government, instead of targeting the rebels, began exterminating their people - against the Geneva Convention, which prohibits attacks on civilians. The British Foreign Office admitted in November they did not want to intervene because "it would become bogged down and some new cause for all the jihadists in the world would emerge". Fall-out from the invasion of Iraq means the West hesitates to stop a genocide that has nothing to do with it, and so, unpunished, Bashir's storm troopers ethnically cleanse and mutilate villagers for days at a time.

The children have four people to thank for the airtime: Hotel Rwanda star Don Cheadle, hollow-eyed at vibrant genocide; real Hotel Rwanda manager Paul Rusesabagina; crusading congressman Ed Royce and John Prendergast. With his back-to-front baseball cap over less-than-military hair, Prendergast isn't your typical peacemaker: in the past, he's been kicked out of Sudan and declared an enemy of the state for demanding its government answers to war crimes - and still he refuses to be quiet. Prendergast's informality conceals serious business. The four men are inspecting the refugee camp, and Cheadle is interviewing Prendergast. He chooses his words carefully: "These people have been hit by tsunamis of violence." This phrase will inevitably attract criticism, but Prendergast is used to breaking the rules on what he sees as a race against time to save two million lives: today, Darfur's problem is violence, but if the refugees aren't back on their farms before the planting season, it's Ethiopia all over again.

Among rock stars turned politicos, Prendergast is a politico who seems more like a rock star: endearingly chivalrous and cheeky, he explains that his epiphany came in 1985. "Ethiopia starved," he says. "A million lives. I was stunned by the unfairness. I was 21 and felt I had to go to Africa to learn what was going on. I ended up staying 11 years, writing and working for Human Rights Watch, Unicef - then the White House called." Bill Clinton hired Prendergast in 1996 as one of Africa's most informed specialists on conflict, human rights, aid and counter-terrorism on the National Security Council; later promoting him to the State Department.

Prendergast and Clinton flattered sworn enemies Ethiopia and Eritrea towards a ceasefire. "Clinton sent his former national security adviser Tony Lake," he says. "In Africa, Western leaders usually don't care, sending low-level people." Prendergast says many Africans care more about America than any other country, and the personal touch could help even Uganda's horrible child-army mess. "President Museveni wants the President of the United States to care about what he's doing," he says. "Make him a partner for peace. Really. It's not that much. Sending troops, invading, all that stuff is totally irrelevant." Whether you believe Prendergast is talking common sense or has his head in the clouds, this is uncommon thinking. He's proposing an alternative to sabre-rattling - the backbone of modern foreign policy. But the world has changed. Clinton's no longer in the White House and George Bush is anything but a partnership president - with a massive majority. So how does Prendergast hope to turn the public on to gentlemen's diplomacy?

Now 41, Prendergast works as special adviser to International Crisis Group (CG), which has grown into the world's most respected policy advice organisation, with more than 100 field agents worldwide gathering information and then telling the likes of Jack Straw - the Secretary of State for Foreign and Commonwealth Affairs - how to prevent any impending crisis. "We had a good meeting recently with Straw," says Prendergast. "I think he hasn't had the unvarnished point made directly to him - that the longer the British remain non-aggressive to the Sudanese government, the more it delays peace and emboldens human rights abuses." CG's recommendations, Prendergast notes, "are often strongly critical, even of people giving us money". Yet, in 2003 a fat 40 per cent of its recommendations were adopted by international governments.

Washington DC, a snowy morning in February: Prendergast is at America's brainiest think-tank, The Brookings Institution for a televised debate. Prendergast is going head to head over Darfur with Pierre-Richard Prosper, Bush's ambassador-at-large for war crimes. The atmosphere is heavy: the butchers of Darfur are still at large because Bush refuses to allow them to be tried at the International Criminal Court (ICC). Critics say Bush's problem with the ICC is that it tries war crimes, and therefore might want a word about Guantanamo, Abu Ghraib and invading Iraq.

The moderator asks Prendergast if you had one minute to tell the President what he should do about Darfur, what would you tell him? With a glint in his eye, Prendergast says Bush did, in fact, quiz him intently for advice. "I was at some bill-signing ceremony and he saw me across the room and came over," he marvels. "Then his aide told me that he thought I was Bono." The room of boffins explodes into laughter.

Prendergast's eyes are bloodshot from days on a speaking tour; yet despite his tireless efforts, still Darfur burns. But Prendergast can't stop it because four out of five of the countries who could impose arms embargoes on Sudan's government and confiscate their money are the very countries selling them arms. For years, Prendergast has advocated targeting the ego and wallets of individual perpetrators, rather than the trickle-down diplomacy of blanket sanctions. Prendergast knows the ego-sodden lifestyle the war criminals currently enjoy. "I've visited the ministers' homes, listened to their nonsense." On leather sofas? "Oh yeah, good stuff," he sighs. Plundered cattle, tax and oil money add up to wealth "equivalent to the collective requirement accounts of a very rich town in the US or UK".

Hence Prendergast's new mission. "I can have meetings with White House officials till I'm blue in the face," he says. "Nothing will change without domestic political cost." So Prendergast works 21-hour days to focus goodwill beyond tsunamis, and show voters their own power. And this peacemaker has new weapons. In an age of impunity, it might end up falling to celebrities to save the world.

"I met Angelina Jolie at a reception on refugees," he says. "I was going to see one of my favourite actresses, but she found out I was going to the Congo, wanted to assess their refugee situation, particularly sexual violence - within five minutes we decided we were going together." The result is humanitarian gold dust. "We crafted a strategy. She talked to policy makers, TV crews. Every week somebody calls me because Angelina says we've got to do something - Mira Sorvino wowed Congress advocating for victims of violence. She's a Harvard grad, a very, very intelligent woman with blonde-bombshell status. Senators who won't meet NGOs trip over themselves to meet someone like her."

Prendergast chuckles, but his celebrity missions are not flippant. This is no Band Aid of the heart; he's going straight for root causes. No government wants popular, attractive people drawing attention to its failings. And these actors aren't showboating; as America's powerful broadcasting watchdogs reanimate McCarthyism, politics can severely damage your career, while billboards on Sunset Strip mock celebrities who stumped for Kerry.

Los Angeles, 1 March: I head to the faux Oxbridge towers of UCLA, where Prendergast, Cheadle and actor Ryan Gosling have been invited to explain genocide to the students. The sight of the prime California youth slumped before Prendergast in stretch Gap might make you want to re-criminalise marijuana, but these are tomorrow's media moguls - and they vote.

The electricity of star power shoots through the hall as they recognise Cheadle and Gosling, who implore students to write to their congressmen. Prendergast, on three hours' sleep, breaks internationalism into digestible chunks. The students gradually sit up. He's funny and he's urgent: Rwanda's genocide was tolerated, he points out, because politicians deliberately made it sound more complex than it was. The mission works. Students are "impressed, overwhelmed and excited". Afterwards, Cheadle says: "John continues to make noise about something that needs constant noise. Tony Blair seems like his heart's in the right place. I hope he'll stand up and do the right thing for Darfur". That night, protest letters are retyped on iBooks all over campus. White House officials said they never heard from the American public during the Rwandan genocide. Prendergast won't rest until he makes sure they never use that excuse again.

New York, UN HQ, 28 March: Prendergast is invited to meet Kofi Annan hours before the Security Council vote on Darfur. NGOs have sent their top brass. The UN secretary-general's concern for Darfur is palpable, but he is crippled by the Security Council. Pulitzer winner Samantha Power and a Human Rights Watch spokesperson tell me the British Government is double-dealing on the ICC - professing support while brokering exemption deals for America behind the back of the British public.

Under forceful pressure from Prendergast and the NGOs, Annan arranges an audience for them with the Security Council, but Prendergast doesn't have to wait: as he leaves, a man rushes up to pump his hand, telling him significantly to keep it up. Prendergast looks slightly stunned. I look around to see the same man on a TV monitor: Ambassador Stuart Holliday, one of the key players in the forthcoming Security Council vote - and the future of Sudan.

New York, 5th Avenue, 29 March: Prendergast is rallying lawyers-to-be at the prestigious Cardozo School of Law when CG calls: the Security Council has voted for asset freezes, travel bans and arms embargoes on the guilty. Two days later, America steps aside, abstaining on the ICC - a sign that the US government can be moved. I ask Prendergast if he's happy. "Pleased", he says, but his eyes sparkle.

But thousands of miles away, two million refugees are still on famine's clock and the ticking keeps Prendergast from sleeping more than four hours a night. So he's hatching something big. "A secret," he says. "Tell them it's the human rights versions of a blockbuster. I'm just getting warmed up."