Ask any Nato commander in Afghanistan what is the biggest hurdle to defeating the Taliban insurgency, and there is only ever one answer: the safe havens in Pakistan from where militants can launch strikes in safety.
For years the US has noisily put pressure on Pakistan to clean up its act. All to no effect.
Then, realising that public rebukes were getting it nowhere, Washington went quiet, preferring to put its message across quietly in private.
Last month Pakistan acted, launching hundreds of airstrikes on targets in North Waziristan, home to the Haqqani network – considered the most deadly of Afghanistan's insurgent groups – as well as Pakistani terrorists intent on bringing down the government in Islamabad, sectarian outfits and groups with an eye on Kashmir. Ground troops have followed, sweeping through the area.
The question is: will it work?
American diplomats are not getting carried away. They will wait to see what names turn up on the death roll and whether the offensive stems the flow of fighters and big vehicle-borne bombs from Pakistan. (Incidentally, I now know that a Haqqani truck bomb was the target of the CIA's first drone strike this year, in June, as it trundled towards the border.)
Already, the Pakistani military has got itself in a muddle over whether they are even targeting the Haqqanis – a long-standing proxy – awkwardly talking around the subject when quizzed.
And, this week, in North Waziristan's main town of Miranshah, they gave the clearest sign yet that the big fish escaped before the operation started.
Maj Gen Zafarullah Khan, who is responsible for the town, said:
It’s not possible to create water-tight or airtight compartment where an individual cannot escape. Given the context of the terrain, the context of who they are, it will be wrong on my part to say that they did not escape, yes they did.
They had smelled that the operation is about to be launched. The talks had failed, the build-up for the operation had already begun and they could see that, they could sense and smell and, therefore, the leadership was not here, the leadership abandoned place.
Was it an unguarded moment? Or is the military lining up its excuses and blaming the government for weeks of peace talks that never went anywhere?