The main message from the White House to the American people this weekend is that the president has become a master of U.S. foreign policy.

Here is how David R. Gergen, White House communications director, planned to send the message.

* Step One. Thursday afternoon. Vice President Bush and Secretary of State George P. Shultz return from trips to Europe and Asia, respectively, and make statements to the news media.

* Step Two. Friday. Reagan issues a welcoming statement and poses for pictures with Bush and Shultz in the Oval Office as they report to him. Then they go to the White House briefing room and, with the TV cameras rolling, answer reporters' questions.

* Step Three. On Saturday Shultz was to hold a news conference. It had to be canceled because of the snow. A Friday afternoon meeting between Reagan and some International Monetary Fund officials also had to be canceled; the White House had planned to release pictures of it.

* Step Four. Today Bush is scheduled to appear on a Sunday morning television talk show, with his comments likely to be repeated on the evening news, then again in the Monday morning papers.

"On every message we send, we've got to keep driving it home," Gergen said in an interview last week. "We can't be afraid of repetition. If we are doing our job right, you guys the media will be sick and tired of it long before the message is received in the rest of the country."

All modern presidents have manipulated the media. Devious though that may sound, such manipulation is an important part of governance. But the Reagan administration may do more of it--or simply be more systematic and skilled at it--than many of its predecessors.

White House aides say the media can destroy a president, and that to a large extent they are playing defense. And they are not embarrassed by it.

"You know, I've been in public relations, in public affairs work, and you are always trying to protect your client and show him in the best light," said Micheal K. Deaver, White House deputy chief of staff and chairman of a group that meets every Wednesday and Friday to discuss media coverage.

"And so you are looking for positive things to do," he said, "because you know the press is continually looking for the negative. That is a professional relationship that I understand and the media understand. So we spend a good deal of time trying to show the positive aspects of this administration. You have to, otherwise you'd end up like all the rest of the presidents have ended up." He meant that no American president has completed a second term since Dwight D. Eisenhower.

"It is a daily process," Deaver said as he sat in his office immediately adjacent to the Oval Office, "but it gets concentrated in those Friday lunches. We sit down and talk about how are we going to [proceed] . . . .

"In other words, the press is on a kick, some negative response to this president or this administration, maybe its foreign policy, maybe its domestic policy. Okay, what are we going to do about it? How do we respond to this? And we kick out various ideas from a scheduling standpoint, from a communications standpoint, to get at that. Now that . . . you call that managing the news. I call that defending our record."

Gergen, who also worked for presidents Richard M. Nixon and Gerald R. Ford before Ronald Reagan, is similarly convinced of the need for the White House to try to shape media coverage if the president is to maintain support for his policies.

"I don't see what goes on here as manipulation," he said. "There is a certain sense in which the White House is theater and we put on our show. Particularly with the advent of TV, the White House has become more and more theater, and it is not unnatural that White House staffs over the years have become more and more the station managers. They want to run the show.

"And the press has an interest in saying, 'No. We want to run the show, we want to be the station managers. We'll do the coverage. You guys are just the actors out there, and we'll figure out how it's all going to fit together.'

"Well, there is a natural interplay between those forces, the government and the press," Gergen said. "We sit here in the morning and say, 'this is the story we want to get out.'

"The press has meetings all across the city and in New York by 9 or 10 o'clock in the morning, and they figure out the news story they want to pursue that day . . . . Now some of those stories inevitably are negative, and our job is to make sure people understand our point of view on that story. We can't dominate every story, but we can handle ourselves [in] such a way as to get our message out."

This feeling of a need to "get our message out" has intensified at the White House as the economy and other problems have crowded in on the administration, producing "negative" stories in the news media. That, too, is typical of past presidents. Almost all have had bad spells in their relationships with the press; almost all of the bad spells came when the news itself was bad.

Larry Speakes, the president's spokesman, is quite open about his attempts to shape the news. "You don't tell us how to stage the news, and we don't tell you how to report it," he has said.

According to aides, Reagan believes that recent declines in his popularity derive in part from the media's portrayal of him as having failed with the economy (he especially feels he has not gotten credit for lowering inflation), as being unreasonable in raising defense spending while cutting domestic programs, and as being insensitive to the concerns of minority groups and women.

"Sometimes in the last few weeks the press, like birds flying to a telephone pole, did seem to become excessively negative in their coverage of the president," said Gergen. "The pendulum had swung too far."

Aides were especially unhappy with a recent spate of "disarray" stories about the administration, suggesting the president was losing his ability to lead.

"The press tends to have a pack-herd mentality," Deaver said. "They don't check their facts, a lot of them. They'll go with the story because it appeared in print, not because they checked it out to know that it is in fact true . . . .

"Twenty years ago, that never could have happened in America. People checked their stories out a lot better than they do now. There is so much . . . competition to make the big bucks in journalism that reporters are driven to compete. And that is not helpful.

"I'm not saying it's a conspiracy. It's more of what I said before. This competitiveness on behalf of editors and producers is what is hurting this country . . . . They destroy every hero. We don't have heroes anymore, we don't have anyone to believe in because they strip them naked . . . . If a man is a scoundrel, he ought to be exposed, and he was exposed in the free press in this country for years. But they never took a picture of FDR in his wheelchair because they had enough respect for this office."

Reagan's aides say there have been some complaints about bad press to publishers and networks. They also think coverage has been more favorable lately, partly in response to the president's State of the Union message, his budget and his success in achieving a bipartisan set of recommendations for shoring up the Social Security system.

The bad press nevertheless generated questions internally as to whether the White House staff was doing an adequate job of handling the media. New guidelines were adopted, and all requests for interviews are now supposed to go through Gergen's office.

Gergen said he turns down 10 percent of the requests, some because they are efforts to touch base with every participant in a closed meeting, some because the official involved knows only "snatches of facts" about the intended subject, some for other reasons.

"It cuts down on inadvertent leaks, where you might have been having a relaxed conversation with a reporter and later you'd see that your personal thoughts had gotten into a news story," said Joanna Bistany, a Reagan press aide. "It stopped some people who would leak for ego reasons . . . so they could feel they had done something important."

Reporters do not like the policy: "You have to talk to someone, because Larry Speakes is not plugged in," said James Gerstenzang of the Associated Press. "I think the perception that they are controlling the press hurts them."

In addition to the new interview policy, earlier this month the White House appointed John S. Herrington, an assistant secretary of the Navy, to survey the way the White House relates to the media and key constituencies.

"What I'm doing here is simply a management study," Herrington said, "to see if we have the best possible operation to serve the administration and the president. It's a natural part of the process at midterm. It does not imply criticism or unhappiness with the current operation."

Nevertheless, the White House has plainly become sensitive about the press.

At a recent noon press briefing Speakes exchanged sharp remarks with several reporters after he refused to answer any questions about a comment by the president that it is hard to "justify" a corporate income tax.

At the morning press briefing that day, Speakes had criticized reporters for paying too much heed to what he called a throw-away comment and chastised them for "jumping up and down, lick-ing your chops and doing backflips over the story."

In a recent speech, Speakes joked that the White House is growing close to a "bunker mentality" in dealing with the press.

"No," he told the National Association of Government Communicators, "we're not yet in a bunker mentality at the White House, but I can report that our scouts on the outer limits report that the siege guns are in place and they are aimed at the Oval Office."

In the same speech, Speakes said public opinion is being poisoned by "doom and gloom" stories in newspapers and on television so that it has become difficult to tell whether people think there is a problem with unemployment, for example, or if they have been convinced there is a problem "after they've seen the bad news night after night."

"My question to you is, can the modern presidency survive the modern media?" he said.

Reagan himself has shown irritation with his portrayal in the media. At a celebration of the beginning of his third year in office, he told his political appointees: "This is not time to be swayed by Washington's whining voices and crying towels."

Reagan has also started taking more trips out of Washington to get around the Washington press corps and has begun holding shorter news conferences, in which he reads a statement and questions are limited.

The crafting of the master media strategy is done every day at the White House's senior staff meeting, where the president's aides go over the day's forthcoming news events and the president's schedule, and discuss opportunities for television and still cameras to photograph the president for the next day's newspapers and evening news.

If there is a particularly touchy subject circulating that day, a smaller group will get together after the meeting. These include Gergen, Deaver, chief of staff James A. Baker III, Speakes, White House staff secretary Richard G. Darman and Craig L. Fuller, director of Cabinet administration.

There is also a meeting on media relations every Wednesday, chaired by Deaver, that includes the ad-hoc media team, the president's schedulers and Edward Rollins of the White House political office.

Other participants have included Richard Williamson, departing head of the White House intergovernmental relations office, and Elizabeth Hanford Dole, who was head of the president's office of public liaison with political groups ranging from churches to women until she became transportation secretary.

"We sit down with a detailed schedule," said Gergen, "for the next three to four weeks, and we also have a block schedule for 30 to 60 days . . . . We look at things on the schedule with an eye toward the story line we are trying to develop that week or that month, and other things you put on the schedule because they are good events in and of themselves."

On Thursdays another public relations group meets to review the foreign coverage the president is getting and to plan for stories to appear not only in the United States but also abroad.

On Fridays, Reagan's public relations advisers meet again for lunch at Blair House to brainstorm. This group includes Deaver, Baker, Gergen, Darman, Fuller, Williamson and Michael A. McManus, a Deaver deputy in charge of scheduling.

The media live off their complicated relationship with the White House just as the White House lives off the media, but recently there have been some complaints from journalists.

These complaints reached a high pitch a week ago, when the president called an impromptu news conference to read a statement claiming credit for lowering the unemployment rate. After he answered a few questions, Mrs. Reagan appeared with a birthday cake. The cake-cutting and party on live television went on for more than 10 minutes.

"We were used," said Ed Fouhy, Washington bureau chief of ABC television news, which covered the news conference live on the theory the president would answer questions about the state of the country. "I thought they abused our hospitality."

"I don't understand that," Deaver replied. "All they had to do was turn their TV cameras off . . . . We were all astounded . . . they kept the thing on."