WASHINGTON — Even in Karachi, Pakistan's commercial capital of 10 million, where murder and mayhem have become daily fare, it came as a shock. Gang and drug-related violence, ethnic strife and fighting between rival Shiite and Sunni sects have escalated in recent months, tearing at Pakistan's social fabric. But before the armed assault on three American employees of the U.S. consulate in the capital last week--which left two dead, one an intelligence agent--Westerners had not been targets.

So chaotic is Karachi these days that not only do local police, mostly viewed as corrupt and incompetent, not respond to disorder, but even the Pakistani army, after being called in to restore order, gave up and left. The ambush of a U.S. consulate van at a crowded intersection during morning rush hour is a reflection of a city--and a society--spinning out of control, whose fragile democracy may be unraveling, and whose wobbly relations with the United States may be all the more difficult to realign.

Pakistan's Radcliffe-educated prime minister, Benazir Bhutto, who will meet here with Bill Clinton next month in an effort to improve economic and military ties, swiftly condemned the attack as "part of a well-planned campaign of terrorism." While no group has yet claimed credit for the attack, a senior U.S. official conceded that "it was almost certainly political."

The leading theory, offered by Bhutto's mother, is that the murders were in retaliation for the capture, in Pakistan, of Ramzi Ahmed Youssef, the 27-year-old Iraqi suspected of masterminding the 1993 World Trade Center bombing. Ramzi is awaiting trial in New York.

Another theory is that the assailants may have been working for drug lords (Karachi is a major transshipment center for heroin) who the United States wants extradited to face trial here.

Bhutto's generally cooperative attitude on such issues is not popular in Pakistan, which is increasingly being drawn into the Islamic resurgence stirring the Middle East and Central Asia. U.S. officials, privately bemoaning a lack of leadership by the politically weak Bhutto, fear an erosion of state authority. But it is a circular problem: Handicapped by declining support from the urban middle class and Sunni Muslims in Sind province, and skepticism from the powerful military, Bhutto's political frailty limits her ability to restore order or confidence, which, in turn, emboldens the forces of ethnic and religious intolerance that imperil stability in Pakistan.