The next few days in the criminal trial of former WorldCom CEO Bernie Ebbers should be downright riveting , as Scott Sullivan--the company's former CFO and the prosecution's star witness implicating Ebbers in WorldCom's financial fraud--will be cross-examined by Ebbers' attorney Reid Weingarten.  The confrontation should be fascinating given the people involved and the huge stakes--in the absence of any real "smoking gun" documents, most observers seem to agree that the prosecution's case will rise or fall on whether the jury believes Sullivan.

Sullivan is said to be a brilliant and unflappable.  As described in this article in today's New York Times,

one lawyer who has dealt with Mr. Sullivan in legal proceedings has told colleagues he is "the best witness he has ever defended," calling him "a prosecutor's dream, unflappable and very smart" and someone who "reacts well to curveballs."

Financial analysts who met often with Mr. Sullivan when he was at WorldCom attest to his near-total recall of facts and an instant grasp of financial information, in detail.

He was also a hard worker, according to one former co-worker, who remembers him as one of the last people to leave the office and someone "with his shirt sleeves rolled up."

Unlike Mr. Ebbers, who had a reputation for being moody and irascible, Mr. Sullivan was considered calm and professional. "I never saw him fly off the handle," the former co-worker said. "He never lost his temper, and he treated everyone exactly the same."

Still, it is hugely important to Ebbers' defense that his attorneys effectively undercut Sullivan's testimony against him, a task that will be left to his lead attorney, Reid Weingarten.  The Times article notes that Weingarten

has successfully defended other prominent executives including Mark A. Belnick, the former general counsel of Tyco International.

He also won acquittals for other high-profile defendants like Mike Espy, a secretary of agriculture during the Clinton administration.

His unassuming, down-to-earth style and knack for sniffing out weaknesses in witnesses has won him an impressive reputation in the legal community.

Ebbers reportedly has several avenues that he may take in an effort to undercut Sullivan's credibility.  According to this article in the New York Post,

The cross-examination will surely center on:

* Sullivan's alleged extramarital affairs. The bed sheets — not spreadsheets — side of the case will be aimed at showing how easily and consistently Sullivan could lead a fraudulent life;

* Sullivan's alleged marijuana and cocaine use over the years and his admitted use of coke after working hours with fellow employees.

* The fact there is no written proof that Ebbers directed any part of the fraud. Sullivan has mostly testified about conversations he and Ebbers had about the fraud outside of anyone else's earshot.