Their differing perspectives were delivered to a Manhattan Federal Court Jury of 10 women and two men who are hearing the case before Judge Michael Mukasey.

Before the two sides opened the judge told the panel the case was about whether the destruction of the Twin Towers by terrorists crashing two jetliners on Sept. 11, 2001 "is one event or two within the meaning of the binders or final policy.

"It depends on how occurrence is defined. Insurers prefer a one-event definition; Silverstein parties prefer a two-occurrence definition."

A decision by the jury that there was only one occurrence would mean a $1.1 billion payoff for Mr. Silverstein, but a two-occurrence verdict would result in another trial to determine a payment amount that could total up to $2.2 billion, and to decide the share of each insurer.

Bernard Nussbaum representing Mr. Silverstein said, "We will prove in this trial the nine insurers failed to live up to their obligations."

In the end he told the jury "I believe you'll find that this case is not all that complicated" and involves "two distinct physical losses?separated by time and space."

"The world knows there were two planes and there were two crashes 17 minutes apart, and there were two fires and there were two collapses of the buildings 29 minutes apart," said Mr. Nussbaum, but he noted that fire did not spread between the buildings and one building did not collapse the other."

Mr. Nussbaum said the insurers would "say these attacks were one event?all the result of a single coordinated attack, but terrorist plots and motivations cannot make it one event."

"Insurers say it's one event because it was hatched by Osama Bin-Laden sitting in a cave in Afghanistan, but that was a remote cause and insurers do not cover a remote cause," he argued.

Harvey Kurzwell, representing Travelers Insurance and its subsidiary Gulf, said the event "had a single unitary cause" and "the contract is what matters."

Mr. Silverstein, he advised the jury, "made a deal and now Silverstein is involved in a creative attempt to back out of the deal. Evidence will show it was a single coordinated terrorist attack."

He said Mr. Silverstein had arranged for coverage that would treat a series of losses from one cause as one occurrence because he wanted to avoid paying more than one $1million deductible and "wanted a series of losses as one single event."

Mr. Kurzwell said Mr. Silverstein had not intended to have the nine insurers to have different material terms and "the coverage program was consistent throughout."