After McFarlane

WHEN Alexander Haig became secretary of state, he sought to establish himself as the ``vicar'' of foreign policy. Much concerned with protocol and seating on helicopters, he fought a losing battle for power with the bishops of the White House and left office unhappily.

The quietly intriguing development since his departure has been the way his successor, George Shultz, has assumed the central role in carrying out foreign policy. It is the role for which Mr. Haig yearned, but which eluded him.

Mr. Shultz has consistently maintained that it is the President's foreign policy he carries out. His method of operation is to spend a lot of time with the President, carefully talking things through and making sure there is agreement on what the President wants to do. Then Shultz acts on it.

But the ascendancy of George Shultz in the foreign policy apparatus is one of the clear implications of the departure of Robert McFarlane as national-security adviser.

The Washington press corps has been having a fine old time with the McFarlane story. Mr. McFarlane is supposed to have run afoul of White House chief of staff Donald Regan. Mr. Regan is a man capable of splendid pyrotechnics from time to time. Mr. McFarlane is often taciturn, to the point of being elliptical. But they are both former Marine officers, and there have apparently been some verbal slugfests between them.

Less sensational than the story that McFarlane left in pique is the possibility that he had just had enough of those grinding 18-hour days through which we put some of our top government officials.

At any rate, though Mr. McFarlane's departure may have removed a pole of challenge at the White House for Mr. Regan, the real beneficiary in terms of foreign policy influence appears to be Mr. Shultz.

Shultz and McFarlane worked well together. McFarlane had visited the Shultz country home in western Massachusetts; Shultz had been to McFarlane's place in Virginia.

Nevertheless, the eclipse of McFarlane heralds a decline in the status of the national-security adviser in this administration. Things are now very different from the days when Henry Kissinger held the office and assumed such authority in the White House that one can barely remember who was secretary of state.

McFarlane's own appointment to the job was an effort to lower its profile. Though an immensely able staff man (increasingly on the press and TV circuit toward the end of his service), he was hardly a power in his own right. He has been succeeded by Vice-Adm. John Poindexter, a bright and experienced technician, but one who is expected to have an even lower profile.

When George Shultz was going through his confirmation hearing as secretary of state in 1982, somebody wrote that he was a man to whom power flowed. Although he has had his confrontations and turf battles, he is not a power-grabber or headline-seeker. He has been in and out of government in various Cabinet posts, been a distinguished academic, and presided over a huge and profitable international construction company. He has achieved much, is comfortable with himself, and is not running for anything.

In George Shultz's fourth year as secretary of state, foreign policy power seems to have flowed to him.

For his new national-security adviser, the President chose a technocrat and not some exploding star in the foreign policy firmament like Jeane Kirkpatrick. Mrs. Kirkpatrick's own replacement as ambassador to the United Nations is a man with whom Mr. Shultz is comfortable. Mr. Regan may run Mr. Reagan's household, but it is to Shultz that Reagan listens for expert advice on foreign policy. At the White House, Shultz gets plaudits for the Geneva summit preparation. The Caseys and Weinbergers are still hea rd, but Shultz these days seems to be heard more often.

John Hughes is a Pulitzer Prize-winning journalist who was assistant secretary of state from 1982 to 1984.