By Ilyas Khan
BBC News, Karachi
The deaths of at least 34 people in violent clashes in Pakistan's southern port city of Karachi have brought the anti-government lawyers' movement into a new phase.
The clashes were Pakistan's worst political violence in years
The movement was formed after President Pervez Musharraf suspended the country's chief justice, Iftikhar Muhammad Chaudhry, and for two months has been involved in peaceful protests, attracting increasing numbers of political and civil society activists.
In a climactic rally on 5 May, tens of thousands of people gathered to hear the chief justice in Lahore, capital of the politically important Punjab Province.
Many believed a similar reception in Karachi, the country's financial hub, would cause a permanent dent in Gen Musharraf's power.
Instead, the chief justice found himself stranded at Karachi's airport for nine hours as the city descended into anarchy.
The violence was not entirely unexpected however.
The decision by the Muttahida Qaumi Movement (MQM), an ally of the president, to hold a rally in the city on the same day was widely seen by observers as a serious problem.
The MQM-dominated Sindh provincial government also expressed its concern at the potential clash, and advised the chief justice to reschedule his visit.
9 March: Musharraf suspends Chaudhry for "misuse of authority"
16 March: Violence at pro-Chaudhry rally in Islamabad
3 April: Chaudhry appears before private session of court
6 May: Large rally in support of Chaudhry in Lahore
12 May: Violence in Karachi, ahead of planned rally
But Mr Chaudhry's supporters refused, saying his visit had been planned before the MQM's rally, and called on party to reschedule instead.
The MQM has dominated politics in Karachi since the mid-1980s, often engaging in violent exchanges with rival parties such as the Pakistan People's Party (PPP), the Jamaat-e-Islami, and various ethnic groups in the city.
Since 2002, it has been a partner in the federal government, as well as in the province's government.
Overnight, Sindh's government ramped up security in Karachi.
Hundreds of trucks and shipping containers were brought in to block all routes leading to the airport and the Sindh High Court.
By morning, however, the security forces had virtually disappeared.
A series of small rallies by the MQM merged on the main road from the airport to the centre of the city.
Meanwhile, a series of opposition demonstrations advanced from the city towards the airport.
Armed clashes broke out at half a dozen points along the road whenever the two sides met.
It was only in the evening, after more than 30 people had been killed and 100 injured, that the security services moved in to stop the violence.
The pattern is vaguely familiar.
Pakistan's military-dominated establishment is known to have used armed groups to control elections in the past.
In the past, a decrease in [the MQM's] propensity for violence has invariably led to a decrease in the number of votes it receives
Saturday's violence comes ahead of a general election later this year, in which both Gen Musharraf and the MQM have high stakes.
The president wants to be re-elected by the current parliament before its term ends in October. He also wants to remain head of the army.
Rocked by the crisis over the judiciary, and having no national political support base, observers believe Gen Musharraf wants to foster the support of regional forces like the MQM.
For its part, the MQM is seeking to maintain a stranglehold on Karachi, its sole powerbase, by keeping rival forces in check.
Local commentators say that, in the past, a decrease in its propensity for violence has invariably led to a decrease in the number of votes it receives.
The question is whether Saturday's violence will help further the aims of the president and the MQM.
Gen Musharraf has put up with an unpopular policy of siding with the US in its "war on terror" because of a lack of credible political support at home.
Mr Musharraf has blamed Mr Chaudhry for the violence
He has been courting the opposition PPP, said to be the country's largest political party, to make up for this handicap.
But observers believe Saturday's events will have thrown a possible alliance with the PPP into jeopardy. Sindh has long been the group's main area of support.
They say the violence may now pave the way for the emergence of a combined opposition with the PPP in the lead. Such a coalition would be likely to support the lawyers' movement.
In turn, this will weaken the president's efforts to build domestic support and force him to continue relying on foreign powers for survival.
As for MQM, it has come full circle in its transformation - from a militant organization to a political party, and back.
Over the last 15 years, it has taken pains to shed its narrow ethnic support among Karachi's Urdu-speaking population by forging ties with its Balochi, Sindhi, Pashtun and Punjabi communities.
But many believe Saturday's events have shown instead that Karachi may descend into the same pattern of ethnic strife that pitted the MQM's main support group against the others from 1986 to 1996.