At first, Sunday’s terrorist act seemed like just the latest in a long line of horrific attacks on religious minorities in Pakistan.

Taliban militants assaulted two Christian churches in Lahore. At least 15 people were killed, and more than 70 were wounded.

But then, all of a sudden, the targeted became the targeters.

Scores of enraged Christians marched through Lahore. They lynched and murdered two men. As they lay dying, some members of the mob gleefully took out their mobiles and captured photographs for posterity. It was sickening and macabre.

This is not how victims usually respond to terror attacks in Pakistan.

Typically they grieve quietly, even if defiantly. Recall those Hazara Shias in Quetta standing in the cold rain, flanked by the bodies of the dead and refusing to bury their loved ones until receiving assurances of protection from the state.

This is in marked contrast to the violent retaliations in Lahore.

Ominously, this reaction could mark the start of a dangerous yet sadly logical new phase in Pakistan’s sectarian conflict — one that deepens the fault lines of an already fractured country, and that could one day, bring it to the cusp of all-out civil war.

In Pictures: Tears, anger and agony as Lahore bleeds

I’ve argued previously that sectarianism poses the greatest threat to Pakistan’s long-term stability. Sectarian militancy — even after the much-ballyhooed North Waziristan counterterrorism offensive — enjoys broad reach.

Lashkar-e-Jhangvi, after all, has staged attacks in all four Pakistani provinces. Meanwhile, many Pakistanis embrace the underlying views of sectarian extremists; witness the polls that find that majorities of Pakistanis do not regard Shias as Muslims. This isn’t surprising, given how the Pakistani state has essentially institutionalised sect-based discrimination — from the second constitutional amendment to the blasphemy laws. Then there are the troubling links between sectarian militants and the state.

In essence, sectarian militants benefit from nationwide reach, ample public support for their views, and some support from the state.

Hence the dire predicament faced by Pakistan’s imperiled religious minorities — and the extreme measures to which some of them resorted to in the aftermath of the Sunday church bombings in Lahore.

The Christians that killed those two men did not commit premeditated murder. They were retaliating, and for a simple reason: Like so many other religious minorities in Pakistan, they have been terrified, traumatised, and terrorised for too long, and they know the state will not protect them.

So on Sunday, they decided to take matters in to their own hands.

Out of desperation, they became vigilantes.

This is the context that helps explain why they responded in the way that they did (disturbingly, many on Twitter have drawn equivalence between these retaliatory acts and the terrorist acts that provoked them).

Galvanized by what happened on Sunday, other members of religious minorities could follow suit and lash out violently when their own neighborhoods or places of worship are attacked.

As these violent retaliatory actions mount, the bad apples of society could strike back at vulnerable minorities with tit-for-tat violence — in effect ushering in the very sectarian mayhem that local militants aim to manufacture.

This would be deeply tragic, and not just because of the consequent bloodshed and loss of life.

Despite being ravaged by radicalisation, Pakistani society’s capacity to do great things remains unlimited; many outside observers, including myself, have long admired it for this very reason.

And yet, thanks to an absentee state and a militant juggernaut, it could soon find itself being torn asunder.