The chairman of the House Iran-contra select committee, in a firm lecture to former national security adviser John M. Poindexter, charged yesterday that Poindexter had "locked the president" out of the White House decision-making process, but added that President Reagan had "created the environment" that let it happen.

"If the president did not know what you did, he should have known," Rep. Lee H. Hamilton (D-Ind.) said at the conclusion of five days of testimony during which Rear Adm. Poindexter asserted that he personally authorized the diversion of proceeds from the U.S.-Iranian arms sales to aid the Nicaraguan rebels but never told the president about it. {Excerpts of Hamilton's closing remarks. Page A8}

Displaying an uncharacteristic sternness, Hamilton also raised a broader concern, saying he wondered "what else could have been done in the president's name if this was a detail, a matter of implementation of the president's policies."

Poindexter had insisted that, in approving the diversion, he was merely implementing Reagan's overall Central American policy.

It was a day in which Republicans and Democrats on the House and Senate committees criticized the former national security adviser. Many expressed surprise at Poindexter's assertions of "bad faith" efforts by Congress to undermine the president's foreign policy, "deliberate distortions" of the media, and a bureaucracy that is unwilling to take "high risks."

Even Republicans most sympathetic to Reagan and the contra cause appeared to be concerned about the picture that emerged from Poindexter's testimony of a White House staff that carried out secret policies in the shadow of a highly popular president.

Rep. Bill McCollum Jr. (R-Fla.), a Reagan partisan, said he understood that it was necessary to keep the operational side of foreign policy secret, but he chided Poindexter for adopting a secret policy in support of the contras at the National Security Council, instead of openly confronting Congress.

"Secret policy's what got us here today," he said.

Reacting to Poindexter's repeated defense of his decision to authorize the diversion and his failure to tell Reagan as the Iran-contra affair unraveled, Rep. Michael DeWine (R-Ohio) declared: "You took the key player, the best player out of the game . . . . In essence, I know this wasn't your intent, but in essence you put yourself between Ronald Reagan and the American people, and I think in essence that hurt the president and I think it also hurt the American people."

At the end of the day, Poindexter seemed unmoved by the criticism. To Hamilton he said, "I would just simply say that we'll have to agree, you and I, to disagree, on your interpretation of many of the events. And finally I leave this hearing with my head held high, that I have done my very best to promote the long-term national security interests of the United States."

In addition to the rhetoric, which has become a feature of the final day of testimony by major witnesses, new questions were raised about what the administration did last November when the Iran arms deals became public.

House Majority Leader Thomas S. Foley (D-Wash.) pressed Poindexter on several key events in that period. Each time, Poindexter said he either did not recall the details or the events.

Foley asked Poindexter about a final meeting in November between White House aide Oliver L. North and the Iranian middlemen who had helped arrange the Nov. 1 release of an American hostage in Lebanon in return for 500 U.S.-made TOW antitank missiles.

Chronologies prepared for Poindexter by Marine Lt. Col. North last November report a meeting in Geneva Nov. 9-10 with the intermediaries. And, according to notes made at Poindexter's briefing of the leadership of the Senate intelligence committee on Nov. 21, he reported that "U.S. representatives met in Geneva" after Nov. 7.

North testified that he went to Geneva in that time period, but failed to obtain the release of more hostages.

Yesterday, Poindexter said, "I frankly don't recall when the last meeting was. I would have said October."

A puzzled Foley then inquired, "Was there a meeting?"

"There was contact in November by telephone. I frankly don't recall if there was an actual meeting."

Foley then asked about a Nov. 10 meeting, which was the first time Reagan had discussed the Iran initiative with his top national security advisers since January 1986. Attending were Secretary of State George P. Shultz, Defense Secretary Caspar W. Weinberger, Central Intelligence Agency Director William J. Casey, Attorney General Edwin Meese III, Poindexter and other officials.

The Tower review board said in its report last spring that Poindexter had offered a brief history of the Iranian initiatives at that meeting. Yesterday, Poindexter said, "I don't remember the Nov. 10 meeting."

On Nov. 17, according to Foley, Poindexter's telephone log shows that he received an "urgent" message from Meese at 9:43 a.m.

"I just simply don't recall it," Poindexter said, adding that he did remember talking to Meese many times during November. "But what we discussed in that particular phone call, I'm sorry, I have no way of remembering that."

The next day, Poindexter called Casey, who was out of the country, to ask him to return early to discuss their testimony before the intelligence committees on Nov. 21. According to a CIA transcript of a tape recording of the call, Poindexter made a reference to Meese.

"Ed Meese indicated, uh, he'd, he should want to be helpful and so he would like to be in at least one of the meetings" that the two officials were arranging.

In the same phone call, the transcript shows, Poindexter suggested that he wanted "to spend some time just the two of us." Casey replied: "You set whatever time you'd like for us to get together and have a little talk ourselves."

Sen. Sam Nunn (D-Ga.) suggested that the proposed meeting may have been the informal luncheon that Poindexter had with Casey on Saturday, Nov. 22, and which became the focus of extended questioning yesterday.

According to Poindexter's calendar, the luncheon meeting began at 1:30 p.m. and lasted two hours. Casey and Poindexter were joined by North, who had hurried in from his house in Great Falls, Va.

The day before, Casey and Poindexter had briefed the House and Senate intelligence committees, during which the two had provided misleading information about September and November 1985 arms transfers from Israel to Iran. That same day, Reagan had authorized Meese to start a fact-finding inquiry into the shipments, and Poindexter had destroyed a presidential document authorizing CIA involvement in the second Israeli shipment, accoring to testimony.

Yesterday Poindexter said the only thing he could recall from the luncheon was a Casey "debrief" of his meeting with the two intelligence committees the previous day.

Poindexter said, however, he was certain that they had not discussed the diversion of funds to the contras fighting the government of Nicaragua.

Poindexter said he did not recall discussing the destruction of the presidential authorization with Casey that day, even though Casey had sent it to Poindexter on Nov. 26, 1985, with instructions that Reagan sign it.

He also did not recall discussing the Meese fact-finding inquiry, which was taking place in the NSC offices that same day.

For the second consecutive day, committee members lectured Poindexter about how he views the powers of the president.

Sen. Warren B. Rudman (R-N.H.), a supporter of Reagan and of the contras who has frequently expressed astonishment at the activities of the NSC staff, took issue with Poindexter's belief that Congress' power to appropriate funds should not be used "to restrict what the president can do in foreign policy."

Poindexter indicated he could accept financial limitations, but not restrictions on the president and his personal staff.

Foley attempted to sum up what he understood to be Poindexter's "pessimistic" views of national security policy-making in current conditions. Foley said Poindexter seemed to view the NSC as being surrounded by a news establishment that "deliberately distorts," a Congress that is "reflecting attitudes that are in bad faith" and confront the president's policies, and the agencies of government that are "lacking in enthusiasm."

"That leaves a very small group of people in the National Security Council to whom you would feel comfortable in sharing your plans and proposals for presidential actions," Foley said.

Poindexter responded that Reagan campaigned on his foreign policy and "what we have been talking about primarily in these hearings is how the NSC staff went about implementing these policies that were very public positions that the president took."

That view was challenged later by Rep. Jack Brooks (D-Tex.). "Are you suggesting that the millions of Americans who voted for the president were in favor of sending weapons to the Ayatollah {Ruhollah Khomeini} in Iran?" he asked.

Poindexter said that the Iran initiative was only a "tactical decision," adding, "I think most American people feel that that kind of tactical decision ought to be left up to the president, who has the intelligence and who has the information on which to base the decision."

Tempers flared late yesterday afternoon when Poindexter's attorney, Richard W. Beckler, tangled with Sen. Paul S. Sarbanes (D-Md.), after Rep. Peter W. Rodino Jr. (D-N.J.) had asked whether Poindexter had received a briefing about a controversial U.S. criminal investigation about alleged gun-running by the contras.

After demanding a copy of the memo, which Beckler said he had not seen, the lawyer complained, "This is the 11th hour, we're being shown a memo we've never seen before." When handed the document, Beckler said it did not appear to be addressed to his client and objected to the "inference."

Before he could conclude, Sarbanes broke in and accused him of "coaching the admiral on his responses."

"I have not coached my witness and I am not going to tolerate that kind of inference," Beckler shouted.

Before recessing, the committees released a portion of a deposition from Marine Lt. Col. Robert L. Earl, North's former deputy at the NSC. Earl's testimony raised a possible conflict with North's public story that he shredded documents at the NSC on the morning of Nov. 22, while Justice Department officials reviewed relevant Iran documents in an adjacent office.

Earl said that North did not arrive at the office until lunch time, when the Justice Department officials were leaving to have lunch themselves. Earl testified that the shredder in the office was not working that morning, and that North, in fact, had to take documents that qualified for the "termination department" to the White House Situation Room's shredder.

The hearings will resume on Thursday morning with testimony from Shultz and there were hints yesterday that Republicans may be preparing to challenge him for failing to support the president on the Iran initiatives after his own objection had been overruled.

DeWine asked Poindexter, "The fact is, the sad fact is, that the secretary of state chose to protect his own position, did he not?"

"You could draw that conclusion," Poindexter said.

After Shultz, the committees will hear Meese, and former White House chief of staff Donald T. Regan, who Poindexter said "knew everything about the Iran initiatives that the president was aware of." Poindexter said that Regan, like the president, was not told of the diversion of funds to the contras. Weinberger will testify after Regan.