Karachi is under lockdown after Imran Farooq was murdered outside his home in north London.

Mr. Farooq was the leader of the influential Muttahida Qaumi Movement (MQM), one of Pakistan’s more liberal political parties that draws most of its support from the province of Sindh. The Pakistani government is now bracing for a new wave of ethnic violence in Karachi similar to that which saw dozens killed and hundreds injured after Raza Haider, another MQM member, was gunned down last month while attending a funeral.

The situation in Pakistan is already tenuous at best, and the assassination of Mr. Farooq will only make matters worse. The pressing issues of displaced people, ruined infrastructure, constant Islamic militant attacks, and now the potential for politically-motivated ethnic violence are all combining to create a siege mentality in Islamabad. President Zardari has already clearly started to feel the heat, as he recently called an emergency meeting of top party leaders amid rumors of regime change and martial law.

If the situation on the ground in Pakistan continues to deteriorate, a ‘temporary’ period of martial law or an outright military coup is the likely result.

Jayed Siddiq, the Islamabad editor of the Urdu Nawa-i-Waqt newspaper, speculated that the attack could be politically motivated in the form of an attempt to induce the MQM’s departure from the governing coalition:

“A political motive could prompt the MQM to withdraw from the governing coalition… If there is any evidence that the security forces are behind this or it is politically motivated, then there will be turmoil. The MQM is capable of creating a lot of problems for the government.”