Secretary of State Alexander M. Haig Jr. may be learning the hard way what other strong men have learned before him.The lesson is that it is dangerous to preempt the prerogatives of Ronald Reagan.

In California, a strong-minded executive secretary who sought to speak for Reagan as governor was out of his job within a year. Campaign manager John Sears lasted less than four months after Reagan announced for president in 1979. Now, there are those in the White House who think that Haig is walking the same thin line between glory and political oblivion.

The problem, as one aide explained it, is that Haig speaks with "the imperial we" and in so doing takes to himself what ought to be solely the preserve of the president.

A related problem, from a White House perspective, is that Haig has failed to grasp the preferred Reagan style, which is collegial and harmonious rather than confrontational. Again, this was a central problem for Sears, who tried to get rid of longtime Reagan adviser Edwin Meese III and wound up being fired instead.

"Haig's only experience has been with the military and the Nixon administration, which is almost the same thing," said one high-ranking official yesterday. "That doesn't prepare him for dealing in an atmosphere of give-and-take where everyone has part of the action."

It also hasn't prepared him for dealing with Meese, now the White House counselor and the man on whom Reagan most relies. Meese has a close understanding with White House chief of staff James A. Baker and also with his deputy, Michael K. Deaver, who is trusted by the president.

Cabinet members who have been most successful in the early weeks of the Reagan administration have been those who accepted the idea of this collegial leadership and have tried to program their actions with Meese and Baker -- something Haig apparently finds it temperamentally difficult to do.

"Haig is going to have to accept this in the long run, or he won't have to resign," said one official bluntly yesterday. "He'll be told to leave."

This does not mean that Haig is without assets within the administration. While Reagan didn't know him well, he was the president's personal choice, and largely because he projects the tough, anti-Soviet image that Reagan wants to convey. Reagan is said to have been impressed with Haig in their personal meetings. One of Haig's greatest assets is that Reagan likes him.

But Reagan, despite his "aw shucks" nice-guy style of leadership, has never for long tolerated subordinates who patronize him or who make light of his abilities to other aides. The president reportedly was put off by a Haig statement proclaiming that the Soviet grain embargo, which he has kept at Haig's urging, would "test his mettle."

Another report that circulated back to the White House attributed to Haig the view that he had "turned the president around" on the grain embargo issue. One official who heard this report acknowledged that there was some truth in it but said it was undiplomatic of Haig to proclaim his victory.

The seeds of Haig's difficulty with the White House were sown on Inauguration Day when he presented Baker and Meese with a proposal for an executive order that would make the State Department the lead agency in all inter-agency working groups. This amounted to a subordination of two men closer to the president than Haig is -- longtime adviser Caspar W. Weinberger at the Defense Department, and William J. Casey of the Central Intelligence Agency, who headed Reagan's 1980 campaign.

Baker and Meese stopped the proposed order in its tracks, with the approval of Weinberger and Casey.

Then in succeeding weeks, Haig seemed to be actively working on building a coalition against him in the Cabinet on the issues of the neuron bomb, the grain embargo and auto imports.

"Haig's attitude was aloof and uncooperative," says one official who attended most of the Cabinet meetings where these issues were discussed. "The only way he knows how to come on is full bore -- he's too much a military man."

This same official believes that Haig has the virtues of his defects -- and that these are genuinely attractive to Reagan. The strengths are that Haig is a committed and convincing advocate, and that whatever his problems of temperament, he shares the basic foreign policy goals of the president.

Some members of the White House staff have a problem with the way Haig has articulated these goals, however. At a time when the president is trying to give the highest priority to his economic program, Haig's stark presentation of U.S. military options to congressional committees is seen by some aides as diversionary.

"Everyone agreed we needed to send a signal to the Soviet Union and Haig did it admirably," said one aide. "The question is whether we have to send the signal again day after day."

Top aides in the White House were genuinely surprised when Haig went public on Capitol Hill in his objections to making Vice President Bush head of the crisis management team. Reagan had accepted the idea, which was proposed by Meese, and Haig knew he had accepted it.

"I don't think he knew what he was saying when he testified," said one White House official. "There's no way he could gain by going public with his complaint."

This official called Haig's action "an aberration" that he doesn't expect to be repeated.

Even While House officials who expected an eventual confrontation with Haig to develop don't understand why he chose an already-decided issue on which to pick a public quarrel.

His action already has diminished respect for Haig's judgment, for it needlessly brought into the open an intra-administration battle that top aides thought was mostly under control. The result has been diversionary to the economic program, damaging to the Reagan depiction of forceful, Cabinet leadership and personally harmful to Haig.

But Reagan is an incurable optimist and many of his top aides share his positive views. They believe that Haig is basically "a team player" and that the necessity of working cooperatively has been explained to him in terms he accepts and understands.

If their estimates are wrong, there isn't much doubt that Haig will be leaving, sooner or later.

"We're sure he's a team player," said one high-ranking aide. "After all, that's the kind of people Ronald Reagan wants around him."

It was an unmistakable message that the only way for Al Haig to survive is if he decides to become not the vicar of the president but a cooperative player on the Reagan team.