Cozen gradually moved into insurance subrogation, an obscure but incredibly lucrative practice in which lawyers go after a third party, usually a business, deemed responsible for a fire or other loss. The idea is to recover damages for insurers to help offset what they pay out in claims.

Such was the case in 1993 when the firm represented insurance-industry clients in the first World Trade Center bombing. A truck bomb in the garage beneath the twin towers had killed six people and injured more than 1,000.

Cozen sued the Port Authority of New York and New Jersey, then owner of the towers, showing that the agency had been warned the trade center was vulnerable to just such an attack. Cozen collected $19 million for its client, Chubb.

As it had in disputes over diner and restaurant coverage, Cozen went to trial in liability disputes, forcing much larger payouts in cases that typically settled for as little as 10 cents on the dollar.

Those successes fueled enormous growth. From a handful of lawyers in the late 1960s, Cozen has come to dominate the specialty of insurance subrogation. It has grown to 547 lawyers with 23 offices in the United States, London and Toronto, and has moved well beyond its insurance work with venture capital, white-collar crime and general litigation and other new practice groups. It is the fourth-largest firm, in number of lawyers, in Philadelphia and among the top 100 in the nation.

Among its best-known cases were the 1980 fire at the MGM Grand Hotel in Las Vegas; the 1981 skywalk collapse at the Hyatt Regency in Kansas City, Mo.; and the 1991 fire at One Meridian Plaza, a 38-story Center City tower that burned for 19 hours, killing three firefighters.

In the One Meridian fire alone, the firm recovered more than $110 million for the owner, ER Associates, and the manager, Richard I. Rubin & Co., from an alarm company, contractors, and others held responsible.

For all of that, the firm sometimes struggles for respect. Insurance work can be looked down upon by lawyers at other high-end firms who think it lacks the cachet of huge corporate deals.

Origins of the Saudi case

There is something of the father in the son.

In the Saudi lawsuit, Cozen displays his father's sideline intensity, pushing his lawyers hard to produce facts and legal interpretations that could move the case forward.

He pushes himself hard as well.

He won two varsity letters as a basketball player at Penn. And his tuition to law school there was paid by Baltimore Colts owner Carroll Rosenbloom in gratitude for work Cozen did in the summer and fall after his college graduation, unraveling a disputed insurance claim involving Rosenbloom's Shore home in Margate, N.J. It was Cozen's first insurance win.

Cozen has long been a major fund-raiser for Israeli causes. He serves on the board of Steven Spielberg's Shoah Foundation Institute in Los Angeles, whose purpose is to collect and preserve memories of the Holocaust.

Behind the desk in Cozen's office hang two castings of stones from the Western Wall in Jerusalem. Family photos adorn the office as well.

As the firm weighed whether to sue Saudi Arabia, Cozen turned to contacts in Israel, including Gen. Yoram "Ya Ya" Yair, once a top Israeli military commander, who pointed him toward former military and intelligence officials with expertise in Islamist extremism.

Cozen says his support for Israel had nothing to do with the decision to sue Saudi Arabia, a longtime antagonist of Israel.

"We made a decision based on whether there was a good, viable case of civil liability," Cozen said. "We did not look at any moral or political issue. That was not our concern. . . . There were no moral judgments, no vendettas."

The lawsuit takes shape