For Ronald Reagan, the war and peace controversy now buffeting his campaign was ignited not so much by his political enemies but by the enemy within.

It was Reagan himself who first planted the explosive mines, as long ago as last winter, that are bobbing up now in the waters he must sail this fall. He chose, on those occasions, to frame his plans for global crises in phrases of brinkmanship. And he is learning now that rhetoric laced with brinkmanship inevitably produces only rough sailing in the final weeks of a presidential campaign.

Today, both President Carter and Reagan plan to focus the nation's attention upon the war and peace issue. The president, in a radio address, intends to paint his Republican opponent as a dangerous and warmongering individual for his stands on key international issues.

Reagan, meanwhile, has paid for a half hour of television time at 10:30 tonight, primarily to explain his past positions and to refute the charges that his would be a presidency that would advocate wars.

So far, the president seems to have inflicted damage upon Reagan through his assault on the war and peace issue -- but this happened not so much because the president has fired his salvos with skill but because he could not miss. Carter's assault consisted mainly of rolling his depth charges off the deck and hoping they explode in the general vicintiy of a target.

He has not, thus far, offered a detailed, step-by-step analysis of the consequences of Reagan's proposals. Yet that is at the core of the public concerns that have come to be known by that Tolstoyan label that Carter hopes will prove a worthy subtitle to the Making of the President 1980.

Consider the case of Ronald Reagan and the blockade of Cuba.

There are those who believe that Reagan's first mention last January of the possibility of blockading Cuba to force the Soviets to pull out of Afghanistan was just a careless blurtation. But the Republican nominee's chief adviser on foreign affairs, Richard V. Allen, says emphatically that is not the case.

It was Jan. 26 and Reagan -- a stunned loser to George Bush in the Iowa caucuses -- was conferring with his high command about what he should say in a taped interview with Dan Rather for the CBS show "60 Minutes."

Reagan was in his office in Los Angeles, talking by telephone with Allen, an adviser experienced both in international relations and in the ways of Republican politics, who was at that moment in New Orleans at the Southern Republican Leadership Conference, and with John Sears, then his campaign manager, and his domestic issues adviser, Martin Anderson.

Reagan was looking to reestablish his credentials as the Republican front-runner. He had stepped up his attacks on Carter policies, yet on the question of what to do about the Soviet invasion of Afghanistan, he was philosophically vulnerable. He had, in his courtship of the Iowa farm vote, opposed Carter's grain embargo (as had all of the Republicans except John Anderson). It was in this context, last January, that the suggestion of a blockade of Cuba was born.

"Talk about it as an option," Allen recalls saying to Reagan.

"Yes, exactly," Reagan is said to have responded. "That's what we want to do. It's an option."

The final decision on what to say and how to say it was made just a half hour before the interview was taped.

"I'm suggesting that we might blockade Cuba and stop the transportation back and forth of Russian arms, Soviet military," Reagan said in that television interview, when discussion turned to the question of what to do about the Soviet invasion of Afghanistan. "Their submarinens are based there. They have airplanes and pilots there. They have troops on that island. A blockade of Cuba could be an option."

Reagan's suggestion of a blockade of Cuba, in response to the Soviet invasion of Afghanistan, raises a number of crucial questions that Reagan has thus far not answered. Among them:

If the Soviets do not choose to steer clear of the blockade, and a Soviet freighter attempts to sail to a Cuban port, what should the U.S. Navy do? Fire warning shots and, if necessary, sink the freighter? Or abandon the blockade? w

If the Soviets choose to give their freighter a naval escort, in the company of those vessels and submarines based in Cuba, should the U.S. Navy prepare to attack them, too, in these waters perhaps less than 90 miles from the Florida shore?

And if the Soviets were to scramble their Migs based in Cuba to provide air support -- would this then become air and sea warfare with the Soviets, again in the vicinity of the United States?

Would such a confrontation be limited to this one incident in this one locale -- or could it escalate into warfare between U.S. and Soviet forces elsewhere?

And finally, what are the prospects that such a blockade would successfully pressure the Soviets to withdraw their forces from Afghanistan -- and is it worth the risk of such confrontation?

Reagan has not dealt with such questions in his public comments, maintaining instead that he does not think the Soviets would challenge a U.S. blockade. " . . . this does not envision armed conflict," Reagan said in an Associated Press interview this month. "I doubt that there would be any attempt to violate such a blockade."

So Reagan does not address the contingencies in his own contingency plan, and adviser Allen, who is savvy in the ways of policy and politics, explains why: "That's a question for a policy-maker. And the governor is not yet a policy-maker."

While not a policy-maker, Reagan is an accomplished phrase-maker. And in at least one instance -- his recent statement on the SALT II treaty -- Reagan reached for a phrase and succeeded mainly in giving his opponents new ammunition.

Reagan's position on the strategic arms limitation treaty was laid out first in a Sept. 17, 1979, statement: "I believe the Senate should declare this treaty, fatally flawed as it is, be shelved and the negotiators should go back to the table and come up with a treaty which fairly and genuinely reduces the number of strategic nuclear weapons."

He repeated this position throughout the 1980 campaign. But in his recent interview with the Associated Press, he came up with a wild card.

"The one card that's been missing in these negotiations has been the possibility of an arms race," Reagan said. Urging that the present treaty be scrapped, he went on to say that in the future, a Soviet SALT negotiator "will be far more inclined to negotiate in good faith if he knows that the United States is engaged in building up its military."

Fortified with this quote, the president, his secretary of state and other surrogates have spent the past couple of weeks spreading the message that Reagan want to scrap the SALT treaty and plunge America into a new arms race.

"This is the worst case of exegesis I've ever seen!" declares Reagan's adviser Allen, borrowing liberally from the vocabulary of his Stanford University background. And switching to the vernacular in midstream, he added, "What Carter and Muskie and his cats are doing is outrageous." Reagan's goal is not to scrap SALT, but to build a bigger and better SALT treaty, he says.

But he concedes, at the same time, that his boss did not do himself any political good with his arms-race phraseology. Says Allen:

"I would not have said it that way."