Jury Is Seated at Trader's Trial, Then Is Showered With Jargon But despite the presiding judge's plea to avoid terms like swaps and "synthetic C.D.O." - the judge said "mere mortals don't know what a trading desk is" - both sides dove into descriptions of residential mortgage-backed securities and credit default swaps. It was a clunky opening in Federal District Court for the Southern District of New York for the civil trial of Fabrice P. Tourre, whose work putting together a now-notorious mortgage investment is the focus of the Securities and Exchange Commission's case, after a morning in which nine people were speedily seated as the jury. Mr. Tourre, 34, a Frenchman who was on Goldman's mortgage desk, was the point person in constructing a 2007 debt investment that ultimately failed. As the most prominent target of a government lawsuit tied to the financial crisis, he has become a lightning rod for criticism. Goldman had been charged alongside Mr. Tourre, but chose to settle, paying what was in 2010 a record $550 million penalty, without admitting or denying guilt. During opening statements, lawyers for both the S.E.C. and Mr. Tourre painted differing pictures of what was at stake in what is expected to be a three-week trial. Mr. Tourre has denied wrongdoing. He is the only individual facing charges stemming from the investment product. Matthew T. Martens, the S.E.C."s lead lawyer and the head of the agency's trial unit, argued that the case was about taking on excessive greed and trickery on Wall Street. Contending that Mr. Tourre had misled investors about the true origins of the mortgage investment doomed to fail, he argued that the onetime Goldman employee shirked his legal duties to enrich both his firm and a big hedge fund client. Ultimately, Goldman made $15 million in fees on the investment. The firm's client, the hedge fund Paulson & Company, made an estimated $1 billion. "The defendant knew he was committing a fraud," Mr. Martens said. He later added, "It's a civil case to hold him accountable." One of Mr. Tourre's lawyers, led by Pamela Chepiga of Allen & Overy, instead defended him as merely participating in a game played by intelligent investors. The investment Mr. Tourre assembled was a zero-sum game in which one side had to lose for the other to make money. And one of the firms that the government has depicted as a victim, the bond insurer ACA Management, was well aware of whom it was wagering against. "The most sophisticated bettors in the world were the only ones who got a seat at this table," Ms. Chepiga said. But both sides face the challenge of explaining the complexities of intricate debt instruments to a jury of mostly laypeople. The trial's first witness, a finance professor at the University of California, Berkeley, was enlisted to help define the language of Mr. Tourre's former world, thick with arcana like "collateralized debt obligations" and "special purpose vehicles." Several jurors appeared to take copious notes as the professor, Dwight M. Jaffee, spoke on the general structure of the kind of investment at the heart of this case. Among the jurors are a minister - whose profession conjured a poorly phrased comment by Goldman's chief executive, Lloyd C. Blankfein, when he said he was doing "God's work." The jury also includes a retiree and a former retail stockbroker. For the most part, the judge and the lawyer teams steered clear of jury candidates who professed ties to Wall Street or finance, or those said they had read articles about the case. One woman worked as a mortgage underwriter who had ties to JPMorgan Chase. Another was a day trader who had owned Goldman stock at one point. Neither was seated. Driving the speedy process is the federal judge overseeing the case, Katherine B. Forrest. She joked during the jury selection process that she was maintaining an invisible hourglass. The nine-person jury was selected in less than 90 minutes, with the two teams of lawyers using only two of three rounds of strikes in challenging jurors. And while Mr. Tourre's case has been scheduled for three weeks, the judge said she would try to beat that timetable. "I am known as a judge who moves things along," Judge Forrest said. She later added, "I am a shark on time." She also told jurors that while Goldman had once been a defendant in the S.E.C."s lawsuit, it had settled. Judge Forrest warned the jury not to speculate why the investment bank was no longer part of the lawsuit. Nor were they to regard news articles from 2007 about the mortgage boom as evidence in and of themselves. Staying silent throughout the day's proceedings was Mr. Tourre himself, clad in a dark suit with an orange-patterned tie. During proceedings, he mostly looked at a laptop or leaned over to chat with his lawyer team. But not even the ex-trader was immune to the longueurs of explaining mortgage-backed securities, yawning on occasion during Professor Dwight's testimony. Meanwhile, a small armada of TV trucks was lined up outside the courthouse in Lower Manhattan - but it was not clear that they were all present for Mr. Tourre's trial. There were five trials in the courthouse Monday.