What does Ronald Reagan plan in SALT III negotiations, which he advocated in a paid television address to the nation Sunday night?

What did he mean in speaking to the nationwide audience of "a realistic and balanced policy toward the Soviet Union?"

Does Reagan's proposal for "rapid growth" in U.S. relations with the People's Republic of China envision military cooperation or arms sales to that country?

The Republican presidential candidate did not say in the address, and his advisers either don't know or can't say what details or decisions, if any, lay behind the head-line-making rhetoric.

This lack of information is characteristic of a campaign that has provided little in the way of details of undergird the words of the candidate, who has been insulated and protected in extraordinary fashion from questioners and questions. This scarcity of information has been particularly notable in the area of foreign policy and national security, which has become the central battleground in the final stage of the presidential race.

Does Reagan's plan for the U.S. relationship with the Third World, which he described Sunday night as "an important part of any program for peace," envision U.S. foreign aid levels that are rising -- or falling?

What does he have in mind by saying that "we must restore the ability of the CIA and other intelligence agencies" to warn against terrorism?

What does he mean by providing "the security, the incentives and the quality of life" to compensate U.S. service personnel for the sacrifices they make for the nation?

How would he provide the "margin of safety" which is "the most important of all" for securing the peace, and what would it cost?

Again, the advisers who were responsible for Reagan's address, and who briefed reporters on his "definitive statement" on national strategy, can't say what the answers are.

Reagan's senior foreign policy and defense adviser, Richard V. Allen, and the chief of his foreign policy advisory task forces, Fred Ikle, met reporters Sunday evening to provide backup information and answer questions about the wide-ranging address. Time and again, when pressed for clear statements of what the candidate meant, the advisors were unable to provide the answers.

The headline-making centerpiece of the address was Reagan's announcement that "as president, I will make immediate preparations for negotiations on a SALT III treaty" between the United States and the Soviet Union.

There was no explanation in Reagan's address of the nature of the SALT III negotiations that he has in mind. Reporters at the Sunday briefing expressed bewilderment about how SALT III negotiations could begin if SALT II, which Reagan opposes, is scrapped.

Allen said Reagan has a "firm intention" to include in the proposed negotiations "those component parts of the existing [SALT II] agreement that might be useful or applicable."

The matter, he said, is "under constant review," adding that this statement is "definitive."

When asked what parts of the lengthy SALT II would be preserved; for the hoped-for successor negotiations, Allen replied that "we won't be specific now."

A reporter noted that the administration headed by Jimmy Carter had begun its term of office by rejecting key elements of the strategic arms agreement that had been negotiated with the Russians by its predecessor, the Ford administration. The Soviet Union, the reporter went on, was "totally unresponsive" to this change of direction.

Ikle, who served as director of the Arms Control and Disarmament Agency in the last years of the Ford administration, said Carter's sudden shift in March 1977, to a plan for "deep cuts" in strategic arms was "not a good test" of such a change in direction because it was poorly executed. He gave no details, however, of how Reagan would go about the task.

In a policy statement Jan. 31, Reagan said he would be prepared to discuss a future arms limitation agreement with the Russians after Soviet behavior indicates "that a reversal of current Soviet policy is credible."

A senior Reagan political aide, asked yesterday when the candidate decided to advocate SALT III negotiations on an "immediate" basis, quipped, "When he saw the [television] script, I guess."

In the Sunday address Reagan called for "a realistic and balanced policy" toward the Soviet Union, which he previously had said "underlies all the unrest that is going on" in the world.

Asked what Reagan's new words mean, and specificially what Reagan would do and not do with respect to the Russians, Allen rold reporters, "The governor would take account of the actualities in U.S.-Soviet relations and particularly the reality of the continuing Soviet military buildup."

At another point Allen said that Reagan believes "there is plenty of room for cooperative arrangements" with the Russians along the lines of those pursued by previous administrations during periods of detente, if a policy review -- after next Jan. 20 -- indicated that U.S. interests would be served.

Asked if Reagan would lift the partial embargo on U.S. grain sales to the Soviet Union, an embargo he criticized in his campaign, Allen said, "He [Reagan] has not indicated specificially what he would do."

Reagan called Sunday night for "expanded trade, cultural contact and other arrangements" to further a period of "rapid growth" between the United States and the People's Republic of China. Asked if the "other arrangements" include military cooperation and arms sales, Allen said military cooperation is "an open question" and arms sales to China are "something that would be reviewed."

Reagan devoted a section of his speech to "a policy to assist African, and Third World development," which he called "an important part of any program for peace."

While he spoke of the need for U.S. private investment in Africa, he did not express any policy views about official U.S. aid programs to Africa and the rest of the Third World.

Allen, under questioning, said Reagan considers foreign aid "a valuable tool of American foreign policy, a requirement, an imperative to assist nations that could use our help."

The adviser said it is "an open question" how much money Reagan has in mind to pursue aid programs. Asked if Reagan has decided, even in general terms, whether he wants foreign aid expeditures to go up, or to go down, if he is elected, Allen said, "That will be examined and reviewed, early on."

Asked for specifics of the program to "restore the ability of the CIA and other intelligence agencies" to combat terrorism, Allen said, "That's a matter we'll take up in a new administration. It's under study at the present time."

In calling for increased compensation for military personnel, Reagan was endorsing the sentiments of a majority of Congress, which recently raised military pay by 11.7 percent and increased other benefits to improve service life. Carter opposed the military pay increase.

However, Reagan did not spell out what more he has in mind for the military in the way of increased pay or other benefits, other than to say that they should be comparable to what is available in the private sector." He did say that he would ask for reinstatement of the GI Bill, under which many veterans have received schooling. Congress is considering such a plan.

Allen said Reagan has not decided how much he would spend for the military buildup that is envisioned in his call for restoration of a U.S. "margin of safety" over the Soviet Union.

If the "margin of safety" means that the U.S. would build and deploy more ocean-spanning strategic nuclear missiles and long-range bombers than the Soviet Union has targeted at the United States, then the cost, according to the Pentagon, would be $50 billion over the next five years in addition to the $1 trillion already planned for all types of U.S. military forces.

Reagan's advisers said the candidate will be presented with a proposed eight-year military buildup program, which has been under study since last April in "a complex, long and very demanding exercise." The program, they said, is scheduled for completion in December -- at least a month after the election.