At least 90 people have been killed and scores wounded in Pakistan's largest city, Karachi, over the last four days. The wave of violence was set in motion when a Pashtun-nationalist Awami National Party (ANP) activist was attacked on Tuesday, an act that led to another ten murders as gun battles broke out in the Orangi Town neighborhood, which has borne the brunt of the violence. Orangi Town is a lower income neighborhood located on the outskirts of the city. The grip on power in Orangi has become tenuous for the ethnic Muhajir Muttahida Qaumi Movement (MQM), Karachi's largest and most powerful political party, as Pashtun migrants have started to settle in the area, bolstering the ANP's potential for power.

Politics in Karachi is a war of demographics, and ethnic capital is its most potent weapon. The MQM since its inception has always had a demographic advantage in the city, but over the years, large scale immigration from the north has slowly eroded this edge. The violent nature of politics in Karachi has meant that as land and votes become more valuable, individual lives begins to lose their worth.

The current explosion of violence is not an aberration, and is especially not new to Orangi Town. 40 people lost their lives in one day last August after MQM parliamentarian Raza Haider (elected from Orangi Town) was assassinated. But then and now, the most dangerous aspect of the violence is that much of it is arbitrary. We refer to them as "targeted killings" but most of them are not. Gunmen open fire on buses suspected to be driven by or carrying Pashtun passengers. Indiscriminate fire is opened on a marketplace because the stores may be run by Muhajirs. People are killed because of their ethnicity and appearance, yet the distinction between both sides has become so weak that anyone in the wrong place at the wrong time can be killed for wearing a Pashtun shalwar kurta, or on the other side the Muhajir staple "pant-shirt." The majority of those killed in the last four days have been civilians caught in the crossfire or those targeted for their ethnicity alone. This wanton carnage works well for the respective political parties, as it perpetuates the propaganda that the other ethnic group is a threat to their existence and helps to establish the party's writ in the neighborhood. The animosity between the communities increases, further entrenching the political parties within their strongholds. Local elections and the local government system have also been a source of great tension, adding fuel to the turf war.

And violence in Karachi isn't restricted to killing. It also works as a form of economic oppression. People in Orangi Town have been rushing out of the area when they have an opportunity, as many businesses are closed, and the area's residents have trouble acquiring basic necessities. This indirect pressure works to drive people out of an area, "cleansing" it, if you will. The financial losses suffered during violence and strikes in Karachi is staggering. Both ethnic groups are affected by this kind of economic warfare, and find themselves pushed out of their respective areas.

The use of violent acts such as the burning of vehicles, stoning of cars,  and the destruction of other property has become an accepted form of protest in this city. Violence is used as a political tool, and no party has made a serious effort to remove it from their repertoire. The MQM is commonly blamed as the dominant perpetrator of violence and extortion in the city, and it has become clear that in order to compete, other parties feel that they have to play the same game. Every major party in Karachi has militant tendencies, and the city is armed to the teeth. From the top politicians, landowners and industrialists to the foot-soldiers of the underworld, guns are more visible than the national flag.

The de-weaponization program that was drawn up by the provocative former Home Minister Zulfiqar Mirza was shelved along with his post in April this year. A Deputy Superintendent of the police (DSP) told me that he has yet to see a government in Karachi that is willing to initiate such a program. Before the city can be disarmed, the assumption that one's political party can police it's own stronghold must disappear. In a city of approximately 15-20 million people, a force of thirty-thousand underpaid and ill-equipped police are expected to keep the peace, while a substantial amount of them are tasked specifically with protecting VIPs. Yet the police force has at the same time become politicized, because political parties don't allow the police to function in an independent capacity. The veteran DSP I mentioned earlier told me that he can only recall one Inspector General of Sindh province, Jahangir Mirza, who was not appointed on a purely political basis and was willing to stand up to powerful, landed, politicians.

The one question that eludes many is how much direct control the upper echelons of the political parties have over the lower cadres. When it is time for a strike, the top leadership has the power to mobilize the entire party to observe and carry out the strike. Is it logical, then, to assume that the control over political violence is the same? Probably not, as so much of the violence is arbitrary, and unrest often provides an excuse to settle many personal and very localized enmities or disputes. Amidst the fog of this particular war, the answer remains elusive.

This spate of violence has revolved around ethnic and political tensions. A week earlier the clashes were of a more sectarian nature. But even though the vast majority of people in Karachi, regardless of their religious sect or ethnicity don't have an interest in the conflict, they are beholden to the interests of the powerful. And Karachi residents have grown tired of having their productivity brought to a halt every few weeks. This year a stunning 490 people have been killed in targeted killings, according to the Human Rights Commission for Pakistan (the BBC reported this week that 1,100 people had been killed this year in Karachi).

The political violence in the city always dies down, but it is never because a political solution has been achieved. It dies down because pitched battles in the streets are not sustainable, not because political parties have laid down their arms. It only comes to a halt when the parties reach the threshold where their own communities start to question their credibility. The resilient -- yet, at times, resigned -- residents on the streets and in police stations cynically say, "martial law is the best revenge."  It is tragically ironic that there is already martial law in Karachi; it's just not the army that is in charge of it.

 Shaheryar Mirza has a masters in journalism and public affairs from American University in Washington D.C. and works as a reporter for Express 24/7 in Karachi, Pakistan. Follow him on twitter @mirza9.