ISLAMABAD // Pakistan is facing a rise in attacks by insurgents who were previously declared defeated after three years of counterterrorist operations.
On June 1, the Tehrik-i-Taliban Pakistan (TTP) launched the first of a series of cross-border raids from sanctuaries in Kunar, an Afghan province that rivals Pakistan's North Waziristan tribal region for the title of "centre of global terrorism".
Crossing in their hundreds, the insurgents have struck in Dir, a district of the north-west Khyber-Pakhtunkhwa province, and the Bajaur and Mohmand tribal regions.
The regions, formerly a stronghold of Al Qaeda and the probable former residence of Ayman Al Zawahiri, the new leader, were recaptured in January 2009 after the government ordered air force bombings for the first time.
But, as has invariably been the case with all counterterrorist operations since, the Pakistani military failed to capture the key TTP leader in Bajaur, Maulvi Faqir Mohammed, a close associate of Zawahiri.
Pakistani security analysts are convinced that the military's Inter Services Intelligence directorate had purposefully avoided headhunting the TTP leadership in Bajaur and elsewhere.
The intelligence community thought that a concerted campaign would force the terrorist leadership's hand, with devastating consequences in the Pakistani hinterland.
Subsequently, the Bajaur-Dir-Mohmand TTP leadership nexus, sitting comfortably in the Kunar and Nangarhar provinces of Afghanistan, has continued to play cat-and-mouse with the Pakistani military, preventing it from redeploying assets to other insurgent regions.
Nonetheless, the military felt confident enough to order about 50,000 displaced residents to return home in April.
The tactic of not making the fight with the TTP personality focused succeeded to the extent that tentative territorial control was regained.
But it also bought time for the TTP to regroup and hit back, much as the Afghan Taliban did after initially lying low after the 2001 US-led invasion.
Pakistan's north-west now faces a security crisis second only to that in the first half of 2009, when militants ruled the tribal regions, seized Dir and Swat, and threatened the writ of the state across Khyber-Pakhtunkhwa.
Audacity and intimidation are the hallmarks of the TTP resurgence. The recent invasions have been by militant units big enough to assault military outposts.
The TTP knows from experience that it cannot take and defend territory against Pakistani air power, so it has adopted the Al Qaeda tactic of striking at strategic targets with the aim of weakening relations between its enemies.
The recent TTP invasions alarmed the Pakistani government, which protested furiously to the Afghan government, and pointedly asked the US why its forces in Afghanistan were not acting to defend its ally.
In retaliation, the Pakistani government has also dusted off a proposal for fencing its border with Afghanistan, an obvious diplomatic spar, considering that Kabul has never accepted the border imposed in the late 19th century by the British Indian colonial government.
Islamabad worries the TTP invasions are part of a wider conspiracy because they have coincided with mounting US activity in Pakistani airspace.
Subsequently, tensions on the border have risen.
The Afghan president, Hamid Karzai, complained on Monday that Pakistani border forces had fired hundreds of "rockets" (probably surface-to-surface missiles) in retaliation, and had exchanged fire with coalition troops.
The following day Pakistan's military spokesman, Gen Athar Abbas, denied missiles had intentionally been fired into Afghanistan, but conceded some fired at retreating militant invaders may have landed there.
Ostensibly, the TTP raids are part of the backlash to the May 2 killing of Osama bin Laden by US soldiers in Abbottabad.
Certainly, that has been demonstrated by the seizure of a naval base in Karachi in May and renewed suicide attacks against paramilitary and police.
But even more sinister has been a new tactic of suicide bomb attacks in crowded retail shops in cities of Khyber-Pakhtunkhwa on Sunday evenings, and renewed attempts to target other soft targets such as hospitals in Karachi and Islamabad.
Ironically, the one thing keeping the whole of Pakistan's north-west from blowing up again is the controversial September 2006 peace agreement between the government and the Ahmedzai Wazir tribe residents in the North and South Waziristan regions.
In effect, this is a deal with the Haqqani Network, designed to split the militants into anti- and pro-government camps, and prevent the kind of intra-terrorist unity that prevailed before the agreement.
However, the pact is being tested by US drone attacks against the network's leaders in the Waziristans and, more recently, in Kurram.
Barack Obama, the US president, last week cautioned that he would not hesitate to order military actions against factions using havens in Pakistan to launch attacks against American troops.
In doing so, he could push Pakistan over the precipice.