President Reagan opened his first nationally televised address on the Iran arms scandal last Nov. 13 with an unusual promise. "Now you are going to hear the facts from a White House source," he said, "and you know my name."

But the investigations into the Iran-contra affair by Congress and the Tower review board have now demonstrated that Reagan's address that night was riddled with errors and misstatements. Some Reagan aides have called it the most untruthful of his presidency.

Interviews with a number of former and current officials who were involved in the speech show that, like many of the other statements emerging during that critical month on the growing scandal, this first major effort was in large measure the work of Lt. Col. Oliver L. North, who wrote the original draft, and of then-national security adviser John M. Poindexter, who verified aspects that others in the White House questioned.

The speech is still a nightmare to some of the White House aides who worked on it and to others who helped Reagan earn a reputation over the years as a powerful communicator. "It was the worst speech he ever gave," said a Republican political strategist who has advised Reagan for more than 20 years.

A reconstruction of the preparations for the speech shows that Reagan was given a series of misleading statements, some relating to his own past actions, and he willingly delivered them on national television.

The basic premise of the talk -- that the Iran effort was essentially a diplomatic enterprise aimed at establishing a relationship with moderate groups in that country and not an arms-for-hostages swap -- was undermined this week by the revelation that Reagan had signed a presidential "finding" on Dec. 5, 1985, explicitly authorizing a trade of arms for hostages.

Reagan had strongly denied making such a trade in the Nov. 13 address.

"We did not -- repeat, did not -- trade weapons or anything else for hostages, nor will we," Reagan said then.

Reagan delivered these remarks even though he had signed the secret finding, and even though two of his most senior aides, Poindexter and Donald T. Regan, then chief of staff, knew the details of the Iran arms transactions. Poindexter testified that despite the stark arms-for-hostages conclusion of the Dec. 5 finding, the intent of the policy was the broader goal of establishing an opening to Iran. Reagan now asserts that he forgot about the original finding, but does not dispute signing it.

The first draft of the speech was not widely known.

A number of officials interviewed for this account said damage control was their primary goal on Nov. 13 -- to put an end to news media reports that Reagan had violated his own policy and traded arms for hostages.

These officials portrayed a White House gripped by a sense of desperation, in part because some believed that secret dealings with Iran could still lead to freedom for two hostages, in part because of the realization that Reagan was vulnerable to charges of flouting his own antiterrorism policy.

The preparations for the Nov. 13 address began at a time of growing strain on the White House staff from a series of national security crises, including the disclosure of Poindexter's "disinformation" memo targeting Libyan leader Moammar Gadhafi, the Nicholas Daniloff affair and the Reykjavik summit. Adding to the problems, Democrats had just won control of the Senate for the first time in six years.

In late October and early November, North also was actively trying to secure the release of more captives held in Lebanon, and this led officials to be extraordinarily cautious about public statements on the Iran initiative.

Poindexter argued that every effort should be made to remain silent. Regan initially agreed, but then began to argue that the best course was for Reagan to make an address stressing that he was not trading arms for hostages.

At one point, Regan and Poindexter had a tense private confrontation over this issue in front of the president, according to a source close to the former chief of staff.

On Nov. 10, according to the presidentially appointed Tower board, Reagan told advisers that he felt the need for a statement but that "we needed to avoid details and specifics of the operation."

Larry Speakes, then the White House spokesman, said Regan asked him in this period for advice and he suggested the president deliver a televised address. But, Speakes said, he offered this caveat to Regan: "Be sure you know everything."

"This was to tell all," Speakes recalled, "to tie the knot and cut the losses."

Many presidential speeches are the product of a wide range of advice from inside and outside the administration and take weeks or months to prepare. But other addresses are drafted quickly by one or more White House aides and not seen by others before they are delivered. The Nov. 13 Iran speech fit in the rushed category.

One of Poindexter's deputies, Rod McDaniel, noted that the president decided only that morning to go ahead with the speech. At this time, nine days after the Iran deal had generally become public, many White House aides say they knew little detail about it. They did not know what had been sent to Iran, when it had been sent or what the relationship had been with the hostages.

The uninformed staff included most of the communications and speech-writing and press staffers at the White House, "none of whom had been briefed into the program at any more than a surface level," one senior official said.

"You have the P.R. types in the White House and they naturally want to put the best face on the situation," said another official who was working in the White House at the time. "But they are devoid of any facts. Then you have to ask, what was the mechanism? It was the NSC. And who? It was Ollie and Poindexter -- people who had an active interest in having this cover proceed. They weren't going to say, 'We were trading arms for hostages all along.' The control point, the only source, was actively interested in concealing it. Nobody told the others the facts were embarrassingly incorrect."

At the time, North was in the midst of preparing chronologies of the arms deals. According to a well-informed source, North began work on the first draft of an address the night before Reagan formally decided to give the speech. The source said this was not unusual because North was considered at the time the NSC staff officer with the most information about the Iran dealings.

On Nov. 13, the NSC draft was circulated to others in the White House. It said that the United States had sought a strategic opening to Iran and had not traded arms for hostages, according to sources who saw it.

Several officials said there were immediate questions about the draft. One assertion that raised eyebrows was a statement that all the weapons shipped to Iran would fit in a single cargo plane. Two aides to Regan recalled last week that they tried to verify this by asking the White House military office to check it with the Pentagon. These aides said they were told that 1,000 TOW antitank missiles were involved and they were reassured by the Pentagon that these missiles could fit. Only later, they said, did they learn that some 2,000 missiles actually were shipped.

When the National Security Council staff was questioned about the facts in the draft speech, one of these aides said, "We got mumbo jumbo."

Unbeknown to Regan's aides, North's draft had also been privately questioned by his colleagues in the NSC. When North was asked whether he was sure the cargo plane reference was accurate, he responded, "Yep," according to a source who was there -- "with a straight face."

Following past practice, the draft provided by the NSC was "polished" by others. Patrick J. Buchanan, then the White House communications director, was chiefly responsible for this, officials said. Buchanan could not be reached for comment. Anthony Dolan, the chief White House speech writer, said he did not revise the document, nor did his speech writers. Other sources said Dolan met that day to discuss the speech with Buchanan and Regan deputy Dennis Thomas, among others.

None of these officials apparently was aware of the secret Dec. 5, 1985, presidential finding, which undermined the main thrust of the planned speech.

The finding said nothing about a strategic opening to Iran, and instead authorized shipment of "certain foreign material and munitions" as part of the effort to free the American hostages in Lebanon.

At 2 p.m. on Nov. 13, Poindexter sought to convince the news media of Reagan's version of events. The admiral appeared at a hastily arranged "background" briefing for reporters in the Roosevelt Room of the White House. Poindexter refused to answer many questions and was clearly unhappy with the decision to give the speech, saying it was being done "with the hopes of stopping speculation and creating more damage."

Asked whether the weapons to Iran were being shipped "with an eye toward" getting the hostages out rather than a strategic relationship, Poindexter said, "That's absolutely incorrect."

Poindexter also said the amount of material sent to Iran was "minuscule." When asked about presidential findings, he did not mention the one in December, which was still in his files, but instead told reporters that Reagan "signed a document that has authorized this project" in January 1986 -- a reference to the second finding.

Asked whether the United States had shipped any weapons before then, Poindexter said, "That would have been illegal and I have said we didn't do anything illegal," but later he conceded there had been one "exception."

Later in the day, before the president's 8 p.m. speech, chief of staff Regan also volunteered to give interviews to put the White House "spin" on the speech. He told The Washington Post that "all the shipments were small in quantity because they'd all fit in one cargo plane had they all gone at one time."

Asked whether the president had ever discussed a link between the arms shipments and the hostages, Regan said, "He was always very careful to say, 'Make sure we're not negotiating here to buy hostages or do anything of that nature.' The president was always very careful not to want to do that."

In the speech that night, Reagan came out swinging against the news media and repeatedly cast himself as the bearer of truth against a tide of rumors.

"Now, my fellow Americans, there is an old saying that nothing spreads so quickly as a rumor," Reagan said. "So I thought it was time to speak with you directly -- to tell you firsthand about our dealings with Iran. As Will Rogers once said, 'Rumor travels faster, but it don't stay put as long as the truth,' so let's get at the facts."

Poindexter was asked last week by Sen. Sam Nunn (D-Ga.) whether he still thinks this part of the Nov. 13 speech was an accurate statement. "Yes, I do," said Poindexter.

But a senior official who remains in the administration said a "valuable lesson" of the Nov. 13 speech was, "You do not protect the president by shielding yourself and others from the facts."