LOS ANGELES – As the trial of the top fund-raiser on Senator Clinton’s 2000 campaign, David Rosen, opened in federal court here yesterday, a prosecutor accused Mr. Rosen of “deliberately lying” about fund-raising costs to maximize the campaign’s financial flexibility in the final weeks before the election.

Mr. Rosen, 40, is facing three felony counts of causing the filing of false campaign finance reports in connection with a celebrity-laden gala fund-raising concert held in Los Angeles on August 12, 2000. He has pleaded not guilty.

In his opening statement, prosecutor Peter Zeidenberg said the $1,000-a-ticket concert came at a critical time for Mrs. Clinton’s Senate bid.

“Hillary Clinton’s campaign for the U.S. Senate was in every sense entering the stretch run,” Mr. Zeidenberg told the jury. “The polls were tight. Money was tight.”

Mr. Zeidenberg painted the event as lavish, and he repeatedly dropped the names of stars who attended, such as Cher, Diana Ross, John Travolta, and Jennifer Aniston.

The problem for Mr. Rosen, the prosecutor said, was that the costs of accommodating those celebrities and throwing a massive Hollywood-style party quickly got out of hand.

“These performers didn’t come to L.A. by bus. They required, many of them, private jets. Cher required her own particular private jet,” Mr. Zeidenberg said.

“As these costs began to mount, this man, David Rosen, began to panic,” the prosecutor said, pointing his finger at Mr. Rosen, who sat alongside his lawyers at a defense table. “He told a friend he thought this was going to be a career killer … that he was going to get fired.”

Mr. Zeidenberg said Mr. Rosen became so concerned about the costs that he came up with a plan to keep most of them off the books. “He came up with a solution: to lie,” the prosecutor said.

The government alleges that, because of Mr. Rosen’s lies, a political committee connected with Mrs. Clinton’s Senate campaign reported that the event cost about $400,000.The true cost was more than $1.1 million, Mr. Zeidenberg said yesterday. The prosecutor said Mr. Rosen “knew there was going to be outrage in the campaign and at headquarters over the expenses and how they got out of control.”

One complication in the prosecution’s case is that the expenses Mr. Rosen allegedly covered up were not paid for by Mrs. Clinton’s campaign. They were covered in large part by a California businessman, Peter Paul, who was looking to promote his newly founded Internet company.

Mr. Zeidenberg told jurors that if Paul’s gifts had been properly reported, Mrs. Clinton’s campaign would have taken a financial hit. “It’s not free money,” the prosecutor said. He said that large “in-kind” donations like Paul’s would actually force Mrs. Clinton to transfer money out of her most valuable “hard money” accounts.

Under a campaign finance law in effect at the time, hard money could be spent directly on Mrs. Clinton’s election bid, while so-called soft money could only be spent on more indirect expenses, like get-out-the-vote efforts.

“David Rosen knew that there was going to be negative impact on that hard-money fund by taking a massive in-kind donation from Peter Paul,” Mr. Zeidenberg said. He said that Mr. Rosen “was involved in every key decision that was made” about the event, but began avoiding information about the costs after the budget was blown. “It’s hard to know the absolute true costs of anything when you literally cover your ears and run out of the room,” Mr. Zeidenberg said.

If convicted on all counts, Mr. Rosen could be sentenced to up to 15 years in prison. His fate will be decided by a jury of seven men and five women that was seated just before the prosecution’s opening statement yesterday. The jury is mostly white, but includes two blacks. At least one juror is Asian.

Mr. Rosen’s lead attorney, Paul Mark Sandler, is scheduled to deliver his opening statement this morning. He declined to respond yesterday to questions about the prosecutor’s arguments.

According to court filings, the defense intends to argue that Paul and the main organizer of the event, Aaron Tonken, were experienced con artists and that Mr. Rosen was, in essence, an innocent dupe. “He was the unwitting victim of Paul’s and Tonken’s machinations,” defense lawyers wrote in a brief filed last week.

At the time, Paul had three felony convictions. He has since pleaded guilty to a stock-fraud charge stemming from the collapse of his company. Tonken pleaded guilty last year to mail and wire fraud in connection with other fund-raising projects. He is serving a 63-month prison term.

The judge presiding over the trial, A. Howard Matz, has given Mr. Sandler permission to tell the jurors today about Paul’s criminal background. During a break yesterday, the defense team briefly displayed a color photograph of Paul on video monitors in the courtroom.

The judge and lawyers have estimated that the trial will take two to three weeks to complete.

A list of 18 people that the government plans to call as witnesses was also disclosed for the first time yesterday. It includes several people who did administrative duties for Mrs. Clinton’s campaign, as well as people Paul and Tonken hired to help organize the gala.

Among the more notable names on the list is a Chicago businessman and Democratic fund-raiser who played a role in arranging the gala, James Levin. Mr. Levin’s involvement in Mrs. Clinton’s campaign caused some embarrassment after it was disclosed that he once owned a strip club.

Mr. Levin has entered into a plea agreement with federal prosecutors, according to newly disclosed court records. No further public details of his guilty plea could be located last evening. Efforts to contact Mr. Levin were unsuccessful.

Also on the government witness list is Melissa Rose, a woman whom Tonken has described as Mr. Rosen’s ex-girlfriend. Mrs. Clinton will not testify in the case, Judge Matz and the lawyers involved said.

“You will hear no evidence that Hillary Clinton was involved in this in any way, shape, or form,” Mr. Zeidenberg told the jurors. “In fact, it’s just the opposite,” he said, arguing that her campaign was deceived about the true costs of the gala.

The head of Mrs. Clinton’s 2000 campaign and one of her closest advisers, Harold Ickes, has been mentioned as a possible witness. However, his name was absent from the government’s witness list. Prosecutors said they do plan to introduce memos Mr. Ickes wrote, urging campaign staffers to keep costs down.

While defense lawyers have declined to say publicly whom they plan to call, in a court filing made public yesterday, they indicated that Mr. Rosen is “likely” to take the stand in his own defense.