Yes, the Taleban are being thumped but . . .

The Pakistani Government and Army have finally decided to heed the words of a former ruler: “No patchwork scheme — and all our recent schemes, blockades, allowances etc are mere patchwork — will settle the Waziristan problem. Not until the military steamroller has passed over the country from end to end will here be peace.”

Did Pervez Musharraf, the former President, say that? No, it was Lord Curzon, Viceroy of India, more than 100 years ago. And for both strategic and humanitarian reasons Curzon added: “I do not want to be the person to start the machine.”

The inhabitants of Waziristan have resisted outside conquest since time immemorial. That is why Pakistan continued the British tradition of indirect rule, and kept only minimal forces in the region.

So crushing the local Taleban and establishing Pakistani authority in South Waziristan is going to be a long, bloody business in the face of bitter opposition backed by much of the local population — a population motivated as much by old tribal traditions of resistance as by support for the Taleban. This operation will cause great suffering to civilians and lead to deep unhappiness among many Pashtun troops in the Pakistani Army. That is why, like Curzon’s government of India, Pakistan has hesitated for so long before “starting the machine”.

The last time it did so on a large scale under US pressure in 2004-05, it suffered humiliating reverses and was forced to make a series of peace deals.

The Pakistani authorities have now decided to act again, in part because of pressure from the US, and from a desire to be seen to do something effective against the Pakistani Taleban to persuade Washington to release the billions of dollars in aid envisaged in the Kerry-Lugar Bill. Above all, however, they have decided to act because they have come to see the Pakistani Taleban as a serious threat to them.

The decisive moment came in April, when after a peace deal that conceded the Taleban demand for Sharia law in Swat, the Taleban immediately moved into the neighbouring district of Buner, barely 60 miles from Islamabad, and threatened the Pakistani state itself. Equally importantly, for the first time the Taleban’s breach of the agreement and open aggression convinced many ordinary Pakistanis to support military operations against the militants. The Taleban had also begun large-scale terrorist attacks outside Pashtun areas. As a result, the Pakistani army in June launched a ruthless counter-offensive against the Taleban in Swat, which cleared them from the valley.

Three questions hang over the operation in South Waziristan: Will it succeed? Will it help the Western effort in Afghanistan? And will it reduce terrorism in Pakistan, which has surged in recent weeks in response to the military’s actions?

If the Pakistani armed forces put forth their full strength, they can gain control of Waziristan in the sense of breaking up open Taleban armed groups. This will not end the insurgency, but it will drive the local Taleban underground or across the border into Afghanistan.

Will it help the fight against the Taleban in Afghanistan? Only to a limited extent and indirectly. No doubt some Pakistani militants who would otherwise have gone to fight there will be killed; but the Afghan Taleban, while linked to the Pakistani Taleban, are also separate from it, with their own bases of support in both countries. These include Jalaluddin Haqqani and his clan based in North Waziristan, and the leadership of the Taleban in the “Quetta Shura” in northern Baluchistan. These groups have not attacked Pakistan, and their leader, Mullah Omar, has repeatedly called on his allies to stop attacking Pakistan and concentrate on the Western forces in Afghanistan.

To have a major impact on the war in Afghanistan, the Pakistani Army would have to attack the Afghan Taleban on Pakistani soil. This is what the US will expect Pakistan to do next — but Washington is likely to be disappointed.

Not only are these old Pakistani allies, and the only allies Pakistan has in the unfolding Afghan civil war; but most Pakistanis draw a distinction between the increasingly condemned Pakistani Taleban and the Afghan Taleban, who are seen as gravely flawed but fighting for the liberation of their country from enemy occupation. “They can be cruel and extreme, but they have a right to fight for their country, and we should not fight against them,” an old shopkeeper in Peshawar told me in July.

Attacking the Afghan Taleban in northern Baluchistan would also stir up the so far peaceful Pashtun population there and undermine Pakistan’s struggle with ethnic Baluch rebels to the south. Pakistani officials therefore hope that instead they will be able to capture some al-Qaeda leaders in South Waziristan and hand them over to Washington. That would please the US and might reduce the pressure on Pakistan.

Finally, will the offensive reduce terrorism in Pakistan? In the medium term, almost certainly not. While some terrorism has been planned by the Taleban leadership from South Waziristan, there is also evidence of the growing involvement of Sunni extremist groups from Punjab, and especially the sectarian group Lashkar-e-Janghvi.

But terrorism and insurgency are different things. Terrorism can exact a terrible toll, but it cannot destroy a state and may even strengthen it. What would have destroyed Pakistan would have been the extension of Taleban authority from one region to another. The Pakistani military have already proved in Swat that they can prevent this — and they are going to prove it again in South Waziristan.

Anatol Lieven, professor of War Studies at King’s College London.