As far as Washington is concerned, the Pakistani raids over recent weeks that have netted scores of Al Qaeda operatives and Islamist extremists from other groups sympathetic to Osama bin Laden's organization came none too soon.
With criticism growing here that the US was not getting much for its billion-dollar partnership with Islamabad, the security operations - carried out with CIA-supplied surveillance equipment and other sophisticated American backing - have put the shine back on US-Pakistani relations.
The arrests, which delivered the very specific intelligence that ultimately led to a heightened terror alert in the US and provided new information on plans for attacks in Europe, exemplify the crucial role of broad international cooperation in the war on terror. The events also vindicate President Bush's decision after the 9/11 terrorist attacks to embrace Pakistani President Pervez Musharraf as a way to press Pakistan - which had maintained good ties with Afghanistan's Taliban rulers - into fighting Islamist terrorism.
Still, the situation is a complex one - with Mr. Musharraf facing assassination threats at home even as the US is looking to him for progress in difficult problems ranging from Al Qaeda and weapons proliferation to the dispute with India over Kashmir. Even experts who recognize the challenges he faces say that especially in the area of political reforms, Musharraf could do more. And the US, they say, will have to do more to encourage economic growth in Pakistan and can't look away as the Musharraf government pays mostly lip service to the need for democratic reforms.
"I haven't seen any signs of any weakening of US-Pakistani relations even though people are grumbling," says Robert Oakley, a former US ambassador to Pakistan. "But at the same time [the Pakistanis] should be encouraged to do more. There's been some over-all progress," he says, "but in terms of movement towards an over-all moderation, I don't think they've done enough."
If last week's arrests of young Islamists from a mosaic of extremist organizations affiliated with Al Qaeda demonstrated one thing clearly, experts say, it is that the pool of terrorist candidates is deep in countries like Pakistan - and won't be emptied through security operations.
The recently concluded 9/11 commission in America took special note of this, singling out Pakistan - along with Afghanistan and Saudi Arabia - as a country requiring special attention from the US. "It is hard to overstate the importance of Pakistan in the struggle against Islamist terrorism," the commission says in its final report.
In just one example of the challenge, the commission reports that in Karachi alone more than 200,000 children are being educated in the city's 859 madrassahs - religious schools that are often a poor child's only opportunity for education, but which in some cases have been "incubators for violent extremism."
Even on the security front, some critics maintain that Musharraf's actions have come in fits and starts rather than as a sustained effort, and have primarily been calculated to keep American attention - and aid - flowing. (Some Pakistanis joke that Musharraf, who launched a first offensive against Al Qaeda into the troublesome tribal region of Waziristan last spring, is waiting for the fall to take down Osama bin Laden and deliver to the US the ultimate October Surprise).
More soberly, some critics assert that forces of the ousted Taliban, still fighting US forces in Afghanistan, are allowed to cross over and regroup in Pakistan with impunity.
But with Pakistan's raids against Al Qaeda nabbing terror suspects with troves of information about apparent links to cell members in the US, no one anticipates an expression of official US impatience with Pakistan any time soon.
The 9/11 commission seemed to recommend a "trust and verify" approach to Pakistan, saying the US should be prepared to make a difficult long-term commitment to the future of Pakistan - with an emphasis on improving educational opportunities - "so long as Pakistan's leaders remain willing to make difficult choices of their own."
Ambassador Oakley says US efforts to prod Pakistan along the road of political and social reform must continue, but will have to be done privately. "There's no point in being more forceful about it in public," he says. "The US is already very unpopular there, and Musharraf is already seen as a US puppet."
Pakistan's military now has some 70,000 troops in Waziristan, hunting for foreign militants. Meanwhile, the extent of the threat to Pakistani leaders is evident from recent attacks: a failed suicide-bomb against prime minister-designate Shaukat Aziz 10 days ago, an attack on an army commander in Karachi in June, and two attempts on Musharraf's life in December.
• Material from wire services was used in this report.