Carnage in Karachi as suicide bombers attack Benazir Bhutto's homecoming parade - Reuters is now putting the death toll at 133. Sad to say, but it's a safe bet that just as many died in the panicked stampede and crush as were killed by the explosions.

It's happened: now attention must turn to the implications. First, let's take a look at the likely culprits and motivations. First among them is the Islamist movement and 'Al Qaeda', the Taliban and 'related groups' such as Jamaat-e-Islami. There's already been heavy fighting in Waziristan this month, and there have apparently been threats to Bhutto from extremist elements in response to her promise to crack down on them. The sensible fingers will be pointing at them first.

On the other hand, many - including Ms. Bhutto's rather indiscreet husband Asif Ali Zardari - will have conspiracy theories of their own. The ISI, once a sponsor of the Taliban, is foremost among the other possible instigators of the bombings. In fact, the ISI would have been in a good position to create a security loophole for the bombers to get through. And also worth noting that the blasts occurred at the right moment for prime-time UK TV and the US evening news, though not for the Pakistani newspapers. It was about international impact as much as anything.

Elements within the ISI - perhaps not under President Musharraf's control - will fear losing their grip on the country should 'democracy' prevail, though it hardly did badly in the '90s last time Bhutto was in charge. But the General himself or his uniformed cronies could also have a hand in things, since a dead Benazir would solve their short-term angst about handing over the reins and declaration of a state of emergency would certainly hold up the 'elections'.

One figure commentators seem to forget about is the current prime minister, Shaukut Aziz. It has to be said that he's done a reasonable job since 2004 and may well resent being demoted back to finance minister. Could he be raising a faction within the government to further his interests?

In effect, it doesn't matter who really perpetrated the outrage, since Pakistani public opinion - volatile at the best of times - is likely to become highly polarized now. What's for sure is that there will be a reaction.

All of the above - Bhutto, Musharraf and Aziz - are seen by many in the country as US puppets. The blasts are therefore not so much about pro-Islam or pro-PML(Q) [ie. pro-Musharraf] but also anti-American. Thus there's a couple of ways the camps could divide.

It's likely that Bhutto's PPP supporters will be enraged and will seek to vent their anger somehow, but whether this will be against the Islamists or the more obvious target of the military regime remains to be seen. Civil society in the shape of the strengthening lawyers' movement may be their key allies in this - but could there be a Devil's deal with the Islamists too in a union against the army? Alternatively, could the army and ISI be in cahoots with the Islamists, as they were in the last elections?

On the other hand, since Bhutto has effectively sold out to Musharraf anyway, it could be that the army sees this another excuse to crack down on militants, as occurred during the siege of the Lal Masjid a couple of months back. For this it will need the PPP's support. Asia Times sees the current fight against militants in Waziristan as "but a precursor of the bloodiest battle that is coming". And that could have wider implications:

A qualified estimate by intelligence officials is that Pakistani military pacification of the Waziristans would slash the capability of the Afghan resistance by 85% as well as deliver a serious setback to the Iraqi resistance.

Back to Karachi. If anything, Bhutto herself is indirectly responsible. Her showmanlike return - complete with a riotous reception on board the flight, swarms of supporters at the airport and rally and all kinds of thetrical gestures like wearing a sloganized baseball hat above her trademark white headscarf and the intended homage to Jinnah's tomb - was engineered to elicit an extreme mass reaction.

Now she's got it. Pakistani politics was galvanised enough as it was, and the bombs will have intensified the situation even further. What will transpire over the next days and weeks remains to be seen.