Even the way the firms are paid underscores their differences.
Putnam's firm usually charges by the hour, and its lawyers get paid whether they win or lose. O'Melveny already has earned millions from the Jackson-AEG case.
Attorneys like Panish are more entrepreneurial. Each case is an investment, which is why his firm agrees to take fewer than 1% of those that come its way. "You have to be a risk taker to be a personal injury attorney," said Jody Armour, a professor at USC's Gould School of Law. "More of a swashbuckler by personality."
They usually are paid a portion of their clients' winnings, as much as 40%, and shell out the money for experts and other costs. If they lose, not only do they not get paid, they could be out a lot of money for their expenses.
"The big-firm lawyers get paid per hour," Panish said, "and we get paid perhaps."
Though corporate lawyers like Putnam seldom take cases to trial, the courtroom is a second home to personal injury attorneys such as Panish. "Since we filed this Jackson case in 2010, Brian Panish by himself has tried more cases to verdict than the entire team of O'Melveny lawyers working on this case have tried in their careers," said Kevin Boyle, Panish's partner.
During a recent week-long break in the Jackson trial, Panish was part of the legal team that won a $17-million verdict for an 85-year-old man whose leg was amputated below the knee after he was hit by a bus.
By the time a case like Jackson vs. AEG gets to trial, said John Nockleby, director of the Civil Justice Program at Loyola Law School, the two sides have already spent months squabbling over schedules, depositions, and expert witnesses.
"When the stakes are huge, as they are in this case, there are enormous pressures on lawyers to perform, to win these battles," he said.
Over the course of the trial, Putnam has directed several pointed accusations at Panish, saying he had "defamed a number of people inside the courtroom and outside the courtroom" and was telling reporters lies.
Putnam declined to be interviewed for this story.
On the other side, Boyle said that O'Melveny has gone out of its way to make things difficult, not even offering the usual professional courtesies, such as the scheduling of depositions or making simple agreements. O'Melveny wouldn't stipulate that Jackson was dead until after the trial had begun.
Asked if O'Melveny looked down on them, Boyle replied, "They certainly act that way. It seems a very coordinated effort of smugness."
Panish remains angry that Putnam accused his firm of leaking sealed emails to The Times. "I'm not happy about our integrity being challenged." Panish said.
Panish said he's gone against O'Melveny before without any problems.
"I don't have any issue with the law firm," he said. "Mr. Putnam doesn't like us. There's not much we can do about it. Everybody in the world's not going to like me."