President Reagan was carrying on at his last press conference about the War Powers Resolution and the 150 crimps that Congress has imposed on the president's power to conduct foreign policy. Before Vietnam, he noted, the United States had waged four "declared wars," but presidents had found the need to use military force 125 times.

What of Vietnam? he was asked. Relishing the opening for an "I-told-you-so," Reagan said that even before he became governor of California in 1967, he had been arguing for a declaration of war. Indeed he had--picturesquely. In October 1965, when the United States was regularly bombing North Vietnam and U.S. combat troops were pouring into the South, private citizen Reagan said:

"We should declare war on North Vietnam. We could pave the whole country and put parking stripes on it and still be home by Christmas."

What's interesting about this is not whether Reagan was right (two Republican as well as two Democratic presidents thought not), but that he still thinks he was right. That invites an unsettling question: How much of the rest of what he had to say in those formative years is still valid as a guide to understanding how the Reagan administration has managed--or mismanaged--to get into such deep trouble in Lebanon, for one example, or in Central America, for another.

Reams have been written about Reagan's mind-set--conservative, Cold Warrior, fixed in concrete--but a recently published book ("On Reagan") by Ronnie Dugger has to be the handiest compendium of the president's spoken words. Dugger on Reagan is not gentle. But Reagan on Reagan is exhaustively researched, including transcripts from the famous radio broadcasts in the 1975-1979 years, transcripts that Dugger claims the Reagan campaign staff "deliberately withheld" from public examination in the 1980 campaign.

Small wonder, when we recall that a key issue was Reagan's trigger-happiness and when you see what the record reveals.

He was an early advocate of the mining of the North Vietnamese port of Haiphong, and spoke wistfully of an Air Force plan for a 90-day assault on 65 military, industrial and transport facilities in North Vietnam that "would have saved all the bloodshed." He favored "hot pursuit" of enemy troops into their Cambodian sanctuaries long before the Nixon invasion of Cambodia, and would have left it up to military commanders to decide whether to invade North Vietnam.

Of any attempt to negotiate our way out of Vietnam, Reagan said late in 1965: "What is there to negotiate? The enemy must get absolutely no gain." After the withdrawal of American forces and the congressional restraints on further U.S. military involvement, Reagan said Congress had acted "more irresponsibly than any Congress in our history" and "had blood on their hands."

Reagan would have halted the conclusive North Vietnamese offensive in May of 1975 with B52 bombers: "Can anyone think for one moment that North Vietnam would have moved to the attack had its leaders believed that we would respond with B52s?" He believed in bombers and overwhelming applications of force: "B52s," he once said, "should make a moonscape out of North Korea if South Korea is attacked."

He drew only a very fine line on resort to nuclear weapons, which, he said, "no one would cheerfully want to use" in Vietnam. But he thought the "enemy" should "go to bed every night being afraid that we might." He set a high store on the use of U.S. troops as a "show of strength" and recommended U.S. peace-keeping interventions in Rhodesia, in 1976, at about the same time in Cyprus--and in the 1975-1976 Lebanese civil war.

During the 1980 campaign he suggested "that we might blockade Cuba and stop the transportation back and forth of Russian arms." His chief opponent, George Bush, didn't quite call this "voodoo" foreign policy, but he did say "that's a lot of macho." Undeterred, Reagan again suggested a blockade, and a message to the Soviets: "Now, Buster, we'll lift it when you take your forces out of Afghanistan."

It is thus not hard to understand why a handful of zealous ideologues, implanted in key positions in the national security apparat, find the president such an easy sell for hard-line designs. The echoes of Reagan's early recorded commentaries can be found in the mining of Nicaraguan ports; in the use of Marines in Lebanon and in the 16-inch shells of the battleship New Jersey firing off the coast; in the administration's cold shoulder to any serious efforts to have the Contadora countries and others negotiate some sort of Central American stability; in the overpowering of little Grenada; in his scapegoating of Congress for Lebanon and Central America.

True, the Reagan record in office doesn't measure up to the Reagan rhetoric when he was not confronted with the checks and balances of an unresponsive bureaucracy, a contentious Congress or fractious allies--not to mention resourceful adversaries. But neither does it argue, in national security affairs, for "letting Reagan be Reagan."