PRESIDENTIAL influence moves here and there. But right now the Reagan associate with the most clout is his chief of staff, James Baker III. This assessment is arguable. In fact, no one would disclaim this more than Mr. Baker, who sees himself mainly as a middleman between the President and those high-level officials who carry out his wishes.
Actually, it's the chief-of-staff team of Baker and his deputy, Mike Deaver, who seem to have the President's ear. That's where presidential influence comes from.
Early in the administration it was Ed Meese, the President's counselor, who became something like an assistant president. Then another longtime sidekick, William Clark, moved into the national security adviser post and carved out an area of influence that of itself diluted Meese's position.
Baker's close-in relationship with the President comes through in his ability to speak for Mr. Reagan on almost any subject. Thus, when he says that Reagan will probably keep his team pretty much intact in a second term, one can conclude that the President certainly isn't going to bring about any shake-up in a new administration. Some Cabinet members and high-level appointees might go - but not at Reagan's behest.
Baker insists that he himself will leave. He wants to get back to Texas and his law practice. His successor? Baker doesn't know. But the so-called ''wisdom'' within the White House now is that Deaver will get the nod.
Deaver, of course, has also talked of leaving government. But Reagan's personal ties are so close to Deaver that the President is expected to be able to prevail on his highly valued and longtime friend to stay on.
Baker's high-riding position these days rests, in large part, on his preeminent role in shaping the President's reelection campaign. He will, as he did in 1980, negotiate the debates with Reagan's Democratic opponent. He says there will be at least one debate - and that Reagan must debate because to do otherwise could feed rumors that the President wasn't up to it.
Baker, too, more than anyone else, is laying out the overall Reagan campaign strategy - including the tone of the new ads, which seek to paint a picture of Reagan-made prosperity. And Baker's advice will be pivotal - his and Deaver's - in determining just how much time the President devotes to stumping the nation in the fall.
Baker sees Reagan's second term as being a continuation of the first - with much emphasis on cutting domestic spending programs and keeping the economy rolling. What will be ''new''? Baker cites Reagan's promise of tax reform and adds that the President, if voted in for four more years, will give much - and perhaps most - of his attention to foreign affairs in an effort to advance the cause of global peace.
Baker for a long time was under attack from the GOP right wing. Baker, after all, had been a top campaign aide to George Bush. But the attacks have ebbed. Critics have apparently concluded that they can't separate Baker from Reagan. And that they would rather not take their chances on a Democrat.
Mr. Baker may not have become an assistant president. But he or Deaver is at the President's elbow almost continually. As one official puts it, ''If you can't see the President, the next best people to see are, first, Baker, or then, Deaver