It is often said that two things bind a country as diverse as Pakistan: Urdu and cricket. After yesterday's shootout on the streets of Lahore, the list has shortened further. The attack on the coach carrying the visiting Sri Lankan team spelled not just the suspension of international cricket - or indeed any international sport in Pakistan. Pakistan has also just lost its last great link with the outside world. A link that had survived military dictators, a nuclear standoff and the decades of conflict with India has just fallen victim to an audacious commando-style raid outside a stadium in one of Lahore's leafier suburbs. Analysts are not exaggerating when they say that the attack poses existential questions for the Pakistani state. If the state can not protect a visiting cricket team from well-aimed and well-prepared terrorism, what can it do?

Not since the Munich Olympics have athletes been specifically targeted - and the ramifications of yesterday's attack spread just as wide. No group has claimed responsibility for the actions of 14 masked and heavily armed men who arrived in rickshaws and all escaped. But the similarities with the attack in Mumbai which claimed 170 lives are evident and legion, and the possibility that the second major headline-grabbing hit could be the work of a hardline Islamist organisation like Lashkar-e-Taiba, on which Pakistan has only just started to crack down, is obvious. India lost no time yesterday in saying so.

If this shooting does not galvanise Islamabad to take action nothing will. Asif Zardari has made an inauspicious start as president. He has locked himself into the otherwordly luxury of his official residence with a handful of advisers, while mayhem reigns in the country outside. If there is a government in power, it is not obvious to its citizens. Barely 100 miles away from Islamabad, he has just surrendered a large swath of territory in the Swat valley to the Taliban. Pakistan's foreign minister pleaded in Washington this week that the deal was not as bad as it sounded. The sharia law that Swat will now be subject to is said to be milder than the traditional kind. But acceptance of sharia by the residents who remain in the valley (half have left) should not be viewed as the triumph of Islamist clerics, but rather as a sign of their lack of faith in the state's ability to protect them.

Closer to home, all bets are off with Mr Zardari's former coalition partner and opposition leader Nawaz Sharif, after the decision by the supreme court to uphold a ban on Mr Sharif's contesting elections due to a past criminal conviction. Was the supreme court right to uphold the judgment? Its ruling was legally consistent. But was the unreformed court acting independently of the president? Probably not. But by refusing to work with the president, Mr Sharif is also responsible for the fallout. All he will achieve is more popularity in a state which his party already controls, but not in Sindh, Baluchistan or the North-West Frontier Province. Mr Sharif's political ascendancy bodes ill for the unity of the federation.

All of which makes the job of Richard Holbrooke, Barack Obama's envoy to the region, a whole lot more complicated. It is hard enough to devise a multinational plan which involves three nations acting in concert to dampen a growing insurgency. It is harder still when two of the nations, Pakistan and India, are regional rivals and rarely far from conflict. It is next to impossible if one key player, Pakistan, starts to fissure into parallel states. Washington and its previous satrap in the region, the ousted president Pervez Musharraf, are far from blameless. But if a flawed but still democratic ruler in Pakistan cannot seize control - if he cannot be seen to be acting in Pakistan's own interest - then other forces will move into the vacuum. The alternative is oft foretold: regime change scripted or enacted by the army.