In a 45-minute news conference last Nov. 25, Attorney General Edwin Meese III transformed what had been a troublesome event for the administration into a major scandal.

In a dramatic appearance at the White House, Meese reported that during a con-gressional ban on U.S. military aid to the Nicaraguan contras, millions of dollars from the U.S.-Iran arms sales had been diverted to help the rebels.

At the time, his revelations seemed to support Meese's assertion that the administration was "doing everything we can to be sure that there is no hint that anything is concealed."

But documents and testimony since obtained by the Tower review board and Congress' Iran-contra committees suggest that the news conference was part of a larger cover-up to protect President Reagan and shift the spotlight to his White Houes aides, especially Lt. Col. Oliver L. North.

On the previous day, North's attorney, Thomas C. Green, had begun a discussion of the diversion with a Meese deputy by saying, "Col. North is, you know, your ultimate Marine, and he wants to step forward and take the spears in his own chest."

At the news conference, Meese denied that the president had knowledge of the diversion and named North as "the only person in the United States government that knew precisely about this." That denial is yet to be refuted and may never be.

However, information disclosed since November indicates that Meese made a number of statements that day about the president and two 1985 arms shipments to Iran that he knew, or should have known, were untrue or misleading.

The attorney general said that the president had not learned of a November 1985 arms shipment until February 1986, that no one in the U.S. government had authorized the November delivery and that both that shipment and one in September "took place between Israel and Iran, {and} did not involve at that time the United States."

It is now known that none of those statements was true. As testimony last week made clear, an administration cover-up of the 1985 deals was going on at the time of the news conference, and Meese was aware of it. The wrong statements Meese made in that conference about the November 1985 shipment coincided with arguments that were invented by those planning the cover-up, according to the testimony of Assistant Attorney General Charles J. Cooper.

The administration was sensitive about the U.S. role in the Israeli shipments of 1985. The September and November Israeli shipments apparently violated the Arms Export Control Act, which governs transfer of U.S. arms to third countries. The November deliveries, in which the Central Intelligence Agency was involved, also required a presidential authorization, but did not have one.

Moreover, an after-the-fact authorization -- the original copy of which is missing from the White House -- bluntly acknowledged that the November transaction was an arms-for-hostages deal. If discovered, Reagan's signature on such an unqualified statement would have proved embarrassing since it conflicted with Reagan's repeated denials that he intended such a barter.

Evidence now before congressional investigators has established that Meese was no novice in these matters when, last Nov. 7, he asked senior aide Cooper to look into the "wrinkles" of the Iran story that had just broken in the U.S. news media.

Eight days earlier, on Oct. 30, Meese had been asked by national security adviser John M. Poindexter to delay a Federal Bureau of Investigation probe into possible involvement of a company called Southern Air Transport in shipment of arms to the contras. Meese has since said that Poindexter justified this request by saying that Southern Air personnel were involved in the arms-for-hostage deal, which was at a sensitive juncture.

Meese's knowledge of the Iranian initiative went back at least as far as Dec. 7, 1985, when he attended a high-level White House meeting with the president before a meeting in London between U.S. and Iranian representatives. On Jan. 7, 1986, and again on Jan. 16, he was involved in discussions with Reagan and others concerning a new presidential authorization for CIA involvement in the arms sales -- one that was signed on Jan. 17.

On Aug. 5, 1986, Meese assured surprised FBI Director William H. Webster, who had just learned of the arms deals, that they were authorized.

In September he authorized electronic surveillance in Washington of visiting Iranian officials who were part of a new channel into the Tehran government with whom North and others were attempting to open negotiations.

The Iran initiative became public the first week in November, presenting the Reagan administration with a series of rapid-fire disclosures, each of which threatened to expose new elements of the previously clandestine operation. Within a few weeks, Reagan was forced to back down on public assertions that the stories had "no foundation," that no "third countries" were involved and that the main purpose was to open a dialogue with Iranian "moderates."

Although the administration said concern for lives of the remaining hostages prompted its reluctance to reveal the entire story, testimony and documents have made clear that another fundamental interest was to conceal the president's role in the questionable 1985 transactions.

For his part, Meese assigned Cooper, 34, a former law clerk for Supreme Court Justice William H. Rehnquist, who had no experience in criminal investigations, as his point man on Iran. But according to Cooper's testimony last week to the congressional committees, Meese never briefed him on his extensive knowledge of the initiative.

On Nov. 17, the CIA and the National Security Council provided Cooper with generally accurate chronologies of the Iran initiatives, including accurate descriptions of the 1985 Israeli arms transfers. Yet Meese, who was briefed regularly by Cooper, attended a meeting on Nov. 20 at which North, CIA Director William J. Casey and Poindexter agreed on a cover story to tell Congress that they did not learn until much later that the Israelis had sent U.S. Hawk missiles to Iran in November 1985.

Those officials agreed on a fictitious story that the Americans believed at the time that "oil-drilling equipment" -- not antiaircraft missiles -- was aboard the plane. But Secretary of State George P. Shultz and his legal adviser, Abraham D. Sofaer, protested this formulation. Shultz had notes showing he knew of the Hawk shipment at the time it occurred.

But when Sofaer tried to reach Meese to tell him the cover story was false and could provoke a political crisis, by Sofaer's sworn account, Meese sent back word through a deputy that "all was well." Meese's message to Sofaer was that he "knew of certain facts that explained all these matters and that laid to rest all the problems that I {Sofaer} might perceive."

On Nov. 22, according to Cooper's notes, CIA General Counsel Stanley Sporkin told Meese that he had been told a year earlier about the November arms shipment and had drafted an authorization to make legal the CIA's participation.

On that same day, Assistant Attorney General William Bradford Reynolds discovered in North's files the so-called "smoking gun" memorandum, in which North in April 1986 proposed taking $12 million from a $17 million profit on a major sale of arms to Iran to support the Nicaraguan rebels.

That discovery and events surrounding it forced the administration to take stock, and ultimately to send Meese before reporters on Nov. 25. Rumors and reports of a diversion were being picked up by Meese's aides, at the CIA and the State Department, and the House intelligence committee on Nov. 21 had demanded a thorough accounting of the funds generated by the arms sales.

The day before asserting at the news conference that North alone knew all about the diversion, according to Cooper, Meese had dispatched an aide, John Richardson, to the NSC to make another search of files to determine that no documents existed tying others to the diversion.

Also on Nov. 24, Meese questioned Poindexter and his predecessor, Robert C. McFarlane, and apparently satisfied himself that he could assert that neither the president nor other Cabinet officials knew of the diversion, as he did on the 25th.

That left one problem: the president's involvement in the possibly illegal, and definitely politically damaging, 1985 arms transfers from Israel.

About 20 minutes into the news conference, the first question was raised about the 1985 Israeli shipments to Iran.

"Exactly what did the president know, and when did he know it?" asked a reporter.

Meese said, "That is still being looked into."

He then advanced elements of the administration's cover story: that the Israelis shipped U.S. weapons in September 1985, without U.S. authorization, and that the administration did not learn that the November shipment contained weapons until early 1986.

In fact, both of these assertions were refuted in chronologies prepared by the CIA and the NSC that had been available to Meese through his deputy and fact-finder, Cooper. The NSC chronology said the U.S. government "acquiesced" in the Israeli sale of 508 TOW antitank missiles in September 1985. The CIA chronology asserted that the Israelis acted "at NSC behest" in that transaction.

Testimony from McFarlane and White House chief of staff Donald T. Regan has established that McFarlane briefed the president in advance of the intention of the Israelis to ship Hawk missiles to Iran in November 1985 to release U.S. hostages, and that the United States would replace those missiles from its stocks.

At the time the Pentagon had already begun to locate Hawks in this country to ship to Israel as replacements.

Sporkin said he was later informed that Reagan had signed an after-the-fact authorization for the CIA to assist in that November shipment. That authorization has never been found.

At the Meese news conference, a few minutes into questioning on this subject, White House spokesman Larry Speakes tried to end the briefing, saying Meese had to attend a luncheon.

But it continued.

A few minutes later, Meese slightly modified his description of the president's knowledge of the November 1985 transaction, saying that Reagan did not have "complete" information at the time.

On the question of the diversion, Meese said, "So far as we know at this stage, no American person actually handled any of the funds that went to the forces in Central America."

That information was nearly identical to what North told Meese two days earlier, although it contradicted what Reynolds had been told the previous day by North's lawyer, Green, and which Reynolds conveyed to Meese. Green told Reynolds the money went to a company controlled by Albert A. Hakim, an American citizen born in Iran.

Meese's statement also conflicted with the description of the diversion contained in North's April 1986 "smoking gun" memo, which specified that $17 million would be transferred to an Israeli account in Switzerland, and then to a "private U.S. corporation."

Congressional sources say they cannot explain why Meese did not rely on that outline.

As the record now shows, his description was not correct. Americans ran the diversion. Iranian funds were channeled to the contras through Swiss bank accounts under control of two U.S. citizens, Hakim and retired Air Force major general Richard V. Secord, both of whom operated at the direction of North. Staff writer Mark Lawrence contributed to this report.