By Damian Grammaticas
BBC News, Karachi
When Pakistan's President General Musharraf suspended the country's chief justice in March, protests and rioting followed. At least 40 people died in two days of violence last weekend, and now the political instability seems to be spreading.
Umair Khan's head was swathed in a bandage.
Pro and anti-Musharraf protests have erupted throughout Pakistan
On one side of his face the skin had been scraped raw. He was bruised and battle-scarred.
He had been propped up on a bed that had been placed outside his home in a non-descript quarter of Karachi.
It took an effort for him to lift himself up when he spoke. But his eyes flashed with anger.
"We will take our revenge," he said. "when we have recovered we will do it. We won't shoot unarmed people like they did, but we will have our revenge."
It was an ominous threat in a city where politics is a tribal, volatile affair.
Pakistan's commercial capital is a giant, sweaty port of 15 million people. It is popularly known as the beating heart of Pakistan.
But Karachi's different communities, Mohajirs, immigrants from India, Pashtuns from the North-west Frontier, and Sindhis, are bitter ethnic and political foes. Their rivalries have often led to bombings and shootings, bloodshed and violence.
General Pervez Musharraf seized power in a bloodless coup in 1999
Last weekend saw the worst bloodletting in years.
Umair Khan, a Pashtun, was marching with other members of the opposition ANP party to Karachi airport to greet Pakistan's suspended chief justice when, they say, Mohajirs from the pro-government MQM party began shooting at them.
Umair was surrounded. His political rivals tried to kill him.
Incredibly, the bullet they fired missed, shaving the side of his head.
Umair escaped. But 12 ANP supporters were gunned down in the streets.
At least 40 people died in two days of violence.
This was just part of a bigger political conflict that is now gripping Pakistan.
The opposition say he wants to install a more pliant judge
It revolves around two men. The chief justice who is fighting to keep his job, and President Musharraf who has suspended him.
Many believe that Mr Musharraf wants the justice, who has a troublesome, independent streak, out of the way before elections later this year.
There could be legal challenges to Mr Musharraf's attempt to win another term as president and stay on as head of the army. The opposition say he wants to install a more pliant judge.
Now all those seeking to dislodge President Musharraf have rallied around the chief justice.
In one of Karachi's best hotels I found a group of lawyers.
Dressed in white shirts and black suits they were tucking into an expensive buffet lunch.
Mr Chaudhry was suspended from his post in March
From the rooftop restaurant you could see right across the city, hawks hovering menacingly above it on the hot breeze from the Arabian sea.
One of the lawyers, a distinguished-looking, white-haired man who introduced himself as Sheikh, opined "Musharraf has made a big mistake. None of us liked the chief justice.
"He was a rude fellow. He abused us all in court. But the way he's been treated is just wrong."
Warming to his theme he went on. "The problem now is we have two men, Musharraf and the Chief Justice, but just one grave that must be filled. One must lose."
His colleagues nodded in assent.
Sheikh's mood was gloomy. "Centrifugal forces are tearing our country apart" he said. "I just don't feel safe when people are shot in the street, left there like dogs, and the police do nothing."
When the chief justice tried to visit Karachi, the government was warned that letting his supporters and the MQM's thugs onto the streets was a recipe for disaster.
It did not stop either rally, but ordered the police to leave their weapons behind that day.
When the firing began, the unarmed police melted away.
I put the charge that the government had at best been negligent, at worst colluded in the killing, to Tariq Azim, Pakistan's State Minister for Information.
Pakistan does appear to be in deep trouble
Smart, trimly dressed, urbane, he threw his hands up as if in despair.
"What could we do?" he said.
"The opposition have been demonstrating for weeks.
"Our supporters said they wanted to go onto the streets too. How could we stop them?
"It's the opposition who are using a purely judicial issue to stir up trouble."
Pakistan does appear to be in deep trouble.
This political battle will determine the future of President Musharraf's regime. The question is whether it will destabilise Pakistan further.
Back in Karachi thousands of paramilitary Rangers were finally deployed to keep order.
We joined them as they patrolled the city's flashpoints.
They swept through in their pick up trucks, fingering their automatic weapons. Opposition supporters eyed them warily.
"You see, with the help of the masses we have restored order," said a tall well-groomed Ranger with an impeccably trimmed beard and an imperious sweep of his hand.
I am not so sure.
I remembered the words of Umair Khan. "We will have revenge."
Pakistan's political battle-lines have been drawn, you are either pro or anti-Musharraf.
The sides are becoming more and more polarised.
And now the struggle has spilled onto the streets the outcome could be hard to predict, even harder to control.
From Our Own Correspondent was broadcast on Saturday 19 May , 2007 at 1130 BST on BBC Radio 4. Please check the programme schedules for World Service transmission times.