The chief export of Pakistan has long been death and jihad, weaponized into a potent religious and political weapon to be used in Pakistan's shadow war against its chief rival, India. Being jihad, the slaughter of rabbis, Jews, women and children, commuters, hotel guests, and various other sundry infidels is of course sanctioned and encouraged. It is a case of classic taqiyya--Pakistan feigns friendship whilst it duplicituously works towards its nefarious and Islamic-inspired ends.
While the rest of the world quickly forgets, Indians have most definitely not forgotten bloody attacks on their embassy in Kabul, earlier bomb attacks in Bangalore, Mumbai and other cities, and a brazen direct assault on their own Parliament in 2001, attacks which in total killed thousands. All these terror attacks bore the fingerprints of either Pakistani intelligence services, and/or terrorist groups allowed to recruit, fundraise and train openly on Pakistani soil.
The Mumbai Massacre appears to be a turning point. The proof of Pakistani complicity in the conspiracy to commit mass murder in Mumbai's luxury hotels, train stations and other targets is damning as it is undeniable. India and their new best friend, the United States, are demanding immediate action, that Pakistan crack down definitively on the numerous jihadist groups that have long called Pakistan home.
This puts Pakistan in a very difficult position. They can either go to war with the significant minority of the population that supports the jihadists, or they can go to war with India who now enjoys the full support of the US. As an article in StrategyPage says rather bluntly, thanks to decades of Pakistan playing with fire, the choice for that cursed country now is either civil war or nuclear war...and there is no option 'c':
Pakistan is being forced into a corner, where the choices come down to civil war with their Islamic conservatives and radicals (about a third of the population), or war with India, which could escalate into a nuclear conflict that Pakistan would lose. The civil war would be messy, but the government would almost certainly win it. Pakistani politicians, being risk averse, are looking for some way out of this mess. There doesn't seem to be one.