The storming of a naval airbase in Karachi last week again focused attention on the Tehrik-i-Taliban Pakistan (TTP), a faction of the Taliban that has explicitly declared war on Islamabad. It is no surprise that analysis of Pakistan's complex militant threat tends to focus on the country's lawless tribal borderlands, from which the TTP hails.
The group launches almost daily suicide bombings in the north-west and has claimed responsibility for a spate of increasingly audacious attacks across the country.
However, Pakistan's security challenges cannot be ring-fenced within the Pashtun-dominated territories. In fact, a far more threatening hub of militancy lies in Punjab province, the country's political and agricultural heartland. Since the 1980s southern Punjab has developed into a breeding ground for radicalism and militancy, and it is there that the conflict for Pakistan's future is being waged.
This conflict is a legacy of General Zia ul Haq's military regime, which spawned and supported an array of militant groups based in Punjab. Fuelled by financial backing from Gulf countries, these groups were nurtured for a dual purpose: to produce fighters for the jihad in Afghanistan, and to promote doctrinaire Sunni interpretations of Islam at home.
Since the Soviet withdrawal from Afghanistan, Pakistan has continued to back some of these Punjab-based extremist groups. The ramifications of this policy still reverberate, not just in Punjab but across the country.
The most visible embodiment of this ongoing state support is the province's well-entrenched militant infrastructure, underpinned by a network of radical mosques and madrasas that recruit and indoctrinate young men. These religious seminaries, according to leaked US diplomatic cables from 2009, are able to entice disaffected youth by exploiting "choking poverty and underdevelopment", especially in parts of southern Punjab and northern Sindh.
Another key factor is a failing public education system that is both under-resourced and out of sync with economic realities. Ongoing charitable contributions from the Arabian Gulf ensure that madrasas are comparatively well funded and well run, thus appealing to a growing number of Pakistan's rural poor.
In addition to undercutting the role of secular public education, the state's explicit encouragement of Sunni orthodoxy has weakened the country's pluralistic Islamic traditions. Since the 1990s, Punjab-based sectarian groups have targeted Shiites, Christians, Ahmaddiyas and other religious minorities with impunity.
The recent bombings of Sufi shrines across the country also threaten the more tolerant culture prevalent in much of rural Punjab and Sindh. Indeed, the state's endorsement of hardline Sunni Islam over other forms of the religion illustrates the wider struggle for Pakistan's Muslim identity.
Flush with official backing and external funding, Punjab-based extremist groups have thrived over the past three decades. In terms of indicators such as recruits, resources and nationwide presence, they eclipse relative newcomers like the TTP.
They are also more closely linked to international terrorist networks. In recent years, for example, most of the senior al Qa'eda operatives arrested in Pakistan were found either in Punjab, or in safe houses run by Punjab-based groups, particularly Lashkar-i-Taiba (LeT). Another organisation is Lashkar-e-Jhangvi, a sectarian force opposed to Shiites, and a key ally of al Qa'eda and the Pakistani Taliban.
As one of the most lethal militant organisations in South Asia, LeT has propelled the insurgency in Kashmir for many years and carried out the November 2008 terrorist attacks in Mumbai. The testimony last week of David Headley, who conducted reconnaissance on Mumbai-based targets for LeT, alleged that the group remains the Pakistani army's preferred proxy against India.
The growth of Punjab-based militant groups makes it tempting to try to segment Pakistan's security challenge along ethnic and geographic lines. The reality is far more complex. In fact, there are significant overlaps and exchanges of personnel, training and other resources between Punjab and tribal-based organisations.
In practice, this means that attacks in urban centres such as Islamabad, Karachi and Lahore - claimed by the TTP - are probably really the product of close collaboration with Punjab-based groups, which have far greater capabilities in those cities.
The militant threat has been exacerbated by the army's selective approach towards the different groups it has cultivated over the years. Its tactic of trying to distinguish between those seen as strategically advantageous and others has undermined security in the country. Recent events make clear that the army's cherry-picking is no longer sustainable. The very groups that were nurtured and provided with sanctuary over the years have now turned their guns on their patrons.
Following the Mumbai attacks, the army was compelled to crack down on Punjab-based organisations, particularly LeT. However, its efforts have been cosmetic at best. For example, the group's founder and presumed leader, Hafiz Saeed, has not been charged with any crime and continues to lead its charitable arm.
The army's unwillingness to sever its ties with such groups, combined with its seeming inability to control their activities, bodes ill for both domestic and regional stability.
While media attention burnishes the stature of the TTP, then, extremist Sunni networks anchored in Punjab represent a far more critical threat.
Urmila Venugopalan is a former Asia editor at Jane's Intelligence Review, based in Dubai
