By Owen Bennett-Jones
Pakistan, one of Washington's new allies, has deployed huge numbers of troops to the remote tribal regions of the country, close to Afghanistan. The US believes there are hundreds of al-Qaeda fighters living in the region, perhaps even Osama Bin Laden himself.
It is, perhaps, too easy to romanticise Pakistan's tribal areas.
The Khyber Pass can be an extremely dangerous area
The tribesmen live by an ancient code.
Their fierce defiance has secured famous victories against powerful enemies.
In 1842, a 17,000-strong British force was marching through the snow from Kabul to the Khyber Pass when the tribesmen struck. Legend has it that only one Briton, a doctor called William Brydon, got out alive.
More recently, when the tribesmen fought in Afghanistan, they humbled the mighty Soviet Union for years, using little more than Kalashnikovs against helicopter gun ships.
And they have also resisted interference from their own, Pakistani, government.
Pakistani law applies only on the main roads in the tribal areas.
Step off the road and your fate is decided by traditional tribal rules interpreted in a jirga, or meeting of tribal elders.
The tribal areas are arid, dusty and hot.
It is a rugged country.
Traditional tribal life is changing as modern influences creep in
The mud-built houses, each one surrounded by high walls, are like forts. Nothing grows there.
And since they cannot farm, the tribesmen scratch a living from smuggling. They call it cross-border trade.
Many of the drugs now grown so abundantly in Afghanistan start their journey to the West through the tribal areas.
Tribal culture still rests on principles that have been in place for centuries: revenge, honour, hospitality and a distinctly old-fashioned view of women.
It is tempting to think that having preserved their way of life for so long, the tribesmen will resist change in the future. But that is not right.
The tribal system is breaking down. In truth, it is remarkable it has survived so long and as some of the more enlightened tribal leaders now accept, in a world of modern communication, their way of life is increasingly unsustainable.
Take Attaullah Mengal from Balochistan.
He has been the most senior Mengal since he became chief way back in 1954.
Tribal elders are realising that modernisation will help them
As a young man, when the tribal system was stronger, he had enormous power running every aspect of life in his tribe. To this day, some tribal leaders still determine inter-clan disputes with trials by fire.
The accused has to walk seven paces on burning embers: if his feet blister, he is guilty.
But Attaullah Mengal says he just does not do that kind of thing, because times are moving on.
And he has also developed a more positive view of education. He says he barely educated his own daughters and now, as he looks back on it, he says he is a bit ashamed.
There is a story about one Pakistani tribal leader who was visited by a government educationalist who offered to establish a school in his area. "I don't want a school," the leader growled. "Tomorrow morning I'll show you why."
At first light, the two men went duck shooting until the tribal leader barked out a command.
Like dogs, the tribesmen around him jumped into an icy lake to retrieve the dead ducks floating there.
He then turned to the educationalist. "Do you really think," he said, "that if these people were educated, they would be prepared to fetch my ducks?"
Well, having just spent a couple of weeks in or around the tribal areas, I would say that kind of thinking is on the way out.
The tribesmen know that development does offer them real hope.
Increasingly, they want roads, electricity and schools.
And in some areas, those kinds of facilities are being installed.
It is patchy, and at best, it is a long-term solution.
And there is a real risk that in the meantime, the vacuum being left by the weakness of the traditional tribal elders will be filled by radical Islam.
Which leads me to Mohammed, who comes from one of the most remote and defiant tribal areas, Waziristan.
He is now 22, and three years ago he went to fight with the Taleban against the Americans. "They were bombing mosques and killing children," he said. "It was my duty to go."
He had only been there for a couple of months when the Americans captured him and shipped him off to Guantanamo Bay for a year.
He is now in a Pakistani prison, which is where I met him.
And I have to say, he was a very hard man.
I only spoke to him for about half an hour or so but he struck me as calm, resolute and quite scary.
Put it like this. I would not want to be kidnapped by him. And I have little doubt that when he is released, he will volunteer for jihad - holy war.
Mohammed combines the brutal violence of tribal culture with Muslim militancy and it is a lethal mix.
Waziristan shows how powerful a force radical Islam can be.
For the past 12 months or so, Waziristan has had the misfortune to be a very active frontline in America's war on terror.
Under US pressure, the Pakistani government has deployed tens of thousands of soldiers and used aerial bombing to flush out a few hundred al-Qaeda suspects and foreign militants who found sanctuary there.
Pakistani soldiers have been deployed to Waziristan
With President Bush's victory, that campaign looks set to continue.
But already the response has been ferocious. The foreign militants, fully supported by young Waziris, have killed hundreds of Pakistani soldiers.
The tribal elders in Waziristan can do little more than make forlorn appeals for negotiations.
But the young Waziris do not want to talk. Inspired by the local mullahs, they are vowing to fight.
A song now available in the markets in Waziristan spells out the danger of the army's decision to use force in there.
"Waziristan has been broken into thousands of pieces," it says, "and each piece will raise the banner of Islam."
From Our Own Correspondent was broadcast on Saturday, 6 November 2004 at 1130 GMT on BBC Radio 4. Please check the programme schedules for World Service transmission times.