ISIS has claimed last Thursday’s massacre at Lal Shahbaz Qalandar shrine-the sickening culmination of a horribly bloody week in Pakistan that featured attacks in all four provinces and three major urban centers over just four days. This isn’t the first time ISIS has taken credit for an attack in Pakistan. It claimed assaults on a police training academy, a shrine, and a hospital in Balochistan last year, and on a bus in Karachi in 2015. Of course, claiming attacks doesn’t have to mean actual complicity. ISIS has been increasingly on the defensive as it suffers territorial losses in its Middle East stronghold. What better way for ISIS to reassert its relevance than by claiming a catastrophic attack that it didn’t carry out? More broadly, Pakistan may be a magnet for militancy, but at first blush it doesn’t provide the most hospitable environment for ISIS. Most local terror groups are allied with al-Qaeda, ISIS’s rival. Also, with notable exceptions like Lashkar-e-Taiba, most Pakistani terror groups are Deobandi, while ISIS is Salafist. And yet, there’s another side to this story that suggests ISIS was indeed involved in Thursday’s blast. In fact, ISIS’s claim of responsibility may underscore a dangerous new phase of militancy in Pakistan. In 2015, writing for Foreign Policy, I described several scenarios under which ISIS could develop clout in South Asia. One involved taking advantage of an increasingly fractured regional militant environment-one dominated by infighting within the Afghan and Pakistani Taliban-and securing the allegiance of disgruntled militants and splinter groups. Tellingly, the Karachi bus attack that year was claimed by both ISIS and Jundullah, a Pakistani Taliban splinter group. Another scenario that I had laid out involved ISIS forming opportunistic partnerships with major terror groups, despite their very serious differences with ISIS. “Within South Asia’s murky militant milieu,” I wrote, “alliances and rivalries are anything but permanent.” Fast forward to today. ISIS boasts a small but brutal contingent of fighters, many of them former TTP fighters, in Afghanistan. Additionally, many recent ISIS-claimed attacks in Pakistan have also been claimed by Lashkar-e-Jhangvi Al-Alami, a faction of Lashkar-e-Jhangvi (LeJ), and by Jamaat-ul-Ahrar (JuA), a faction of the Pakistani Taliban (TTP)-and which for a brief period split off from the TTP. Both LeJ Al Alami and Jamaat-ul-Ahrar are logical partners for ISIS. LeJ shares ISIS’s sectarian focus, and multiple reports contend it has sent members to fight alongside ISIS in the Middle East. A deep, mutual hatred of Shias can apparently transcend differences over al-Qaeda loyalties or Sunni Muslim sect affiliations. Indeed, members of LeJ Al Alami have in fact openly stated they’re cooperating with ISIS in Pakistan. As for JuA? It’s one of the TTP’s most bloodthirsty factions. It rejected the parent organization’s exploration of peace talks with Islamabad several years back, and it has staged many if not most of Pakistan’s major terror attacks over the last two years. JuA seems prepared to work with any Islamist militant outfit willing to kill-including ISIS, with which it has long flirted. On February 10, JuA announced Operation Ghazi, a new campaign of terror. A few days later, the blasts began. Several targets on JuA’s Operation Ghazi hit list-including the judiciary and police-were attacked last week. The uptake? Pakistan could be witnessing a new normal: Collaboration between a sputtering ISIS seeking new partners, and high-octane local militant factions eager to latch on to ISIS’s still-powerful brand. This shouldn’t be surprising. All Islamist terror groups are cut from the same ideological cloth, and marriages of convenience between ISIS and local extremists should never be ruled out-particularly with local groups like JuA and LeJ-al Alami, which remain highly active and lethal despite intensive Pakistani counterterror operations over the last few years. Pakistan has a big new problem on its hands. For a nation that has justifiably touted its counterterrorism successes over the last two years, the emergence of a potential new militant juggernaut is a deeply ominous development.