Since 1995, Liberty Media has had a veto right over Diller's voting proxy on certain matters. Diller and his legal team from Wachtell, Lipton, Rosen & Katz have portrayed this provision as bowing to Liberty's concerns about Federal Communications Commission rules against cross-ownership of broadcasters.

Liberty, on the other hand, has characterized the veto power much more broadly.

The case could come down to a "he said/she said" match between two key lawyers for Liberty Media and IAC over how the veto provision has evolved over the years. It was last revised in 2001, when IAC merged the USA Network with Vivendi Universal.

Testimony from the lawyers who negotiated that deal differed on what kind of veto power Liberty Media retained.

Frederick "Buzz" McGrath, a partner with the New York office of Baker & Botts, who has represented Malone since 1992, testified that the veto clause was a "catchall protection" for Liberty.

But he could not provide evidence to support that recollection when pressed by Lamb.

"Is there anything in the writing from 1995 that confirms that testimony?" the judge asked.

"No, I don't believe so," McGrath responded.

"Did you communicate it to anyone at Wachtell, Lipton in 1995?" the judge then asked, referring to the law firm representing Diller's IAC.

"Not that I recall," McGrath replied. In fact, McGrath repeatedly admitted that there was no written communication confirming the catchall nature of Liberty's right to veto Diller's proxy.

The Diller response to Liberty is that the veto related only to "regulatory" matters, fundamentally the Federal Communications Commission's cross-ownership restrictions.

On this point, Liberty's lawyer, Pamela Seymon of Wachtell, was quite forceful. She testified that "alarm bells would have gone off in my head" had the "contingent matters" provision been a catchall in the 2001 negotiations.

Seymon also agreed that it was "fair" to characterize the veto provision as one that related to regulatory matters. "It's my interpretation," she said.

On Diller's right to exercise the proxy to vote in favor of spinoffs with a single-tier voting structure, Seymon was clear: "As a contractual matter, he can," she testified. "Remember that there is a board of directors here as well."

Seymon has a point: The IAC board last considered the spinoff at a January 16 meeting. Diller gave a speech at the time and Martin Lipton of Wachtell explained the board's liability, or lack thereof, if they voted in favor of the plan. The board has yet to act.

Malone testified that he left the legal details to his lawyers, while Diller was adamant that a veto provision that would have given Liberty Media a catchall would have set off "alarm bells" for him because "a fundamental purpose" of the Vivendi transaction was to "remove the consent rights" that Liberty previously held.

Stay tuned.