Howard Baker's advisers wanted him to resign as Republican leader of the Senate the better to put maximum efffot into his presidential campaign. Instead, the senator from Tennessee decided to take a leave of absence from the leadership post.

That choice explains the curiously insubstantial role Baker has so far played in the presidential jostling. While he commands the personal attributes and the political ground required for a major player, there remains a question about the intensity of his appetite for the presidency.

Baker's personal characteristics stand out. He is experienced, articulate, highly intelligent and well known. Polls in many states show him with about many states show him with about 20 percent of the Republican vote -- behind Ronald Reagan (who gets about 40 percent) but ahead of John Connally (who gets only a little over 10 percent) and the rest of the field.

As a genuine moderate, with a progressive record on such issues as race and foreign policy, Baker can make a strong bid to that wing of the Republican party that supported Ford, Rockefeller and Eisenhower against more conservative candidates. His only serious competition for the support of moderate Republicans is George Bush, the Texan from Connecticut.

While Bush has served with distinction in the Congress, as an ambassador and in the Central Intelligence Agency he fits too easily into the patrician model (Andover and Yale) that conservative Republicans devour every day. Baker, as a Southerner and a son-in-law of Everett Dirksen, is far less vulnerable.

With Ronald Reagan and John Connally competing hotly for the conservative constituency, it is possible the Republican right will exhaust itself. Thus a strong progressive -- namely Baker -- could get the nomination. Once nominated, his moderate position would make him a formidable opponent against Sen. Kennedy and his competence would put him in good position against President Carter. So Baker is one of the few Republicans who could conceivably go all the way.

What disrupts that fine scenario is Howard Baker himself. He behaves much less like a hotshot candidate for the most powerful office in the world than like a Republican senator from the woods of Tennessee -- which he happens to be.

For example, he has relied on the Senate debate of the arms control treaty to put him in the center of political attention. It still might -- if the floor debates is televised. But so far the arms control discussions have been a yawn. Even in Washington few people pay attention, and the nation has turned a deaf ear. So Baker was obliged to advance the kickoff date of his campaign in order to draw attention.

Similarly with respect to organization. Baker has let go by default at least some of the talent and money normally available to moderate Republicans. He has relied heavily on a home-state team led by people without the stature to speak for the candidate when dealing with heavy hitters outside Tennessee. He is only now getting a professional team of organizers to manage his campaign. He still lacks an experienced national figure -- what Sen. Paul Laxalt (R-Nev.) has been for Ronald Reagan -- to speak for him.

To be sure, it is early days and a slow start can be mended. If Baker survives the earliest primaries and does well in some of the Southern states and Illinois, he could fall heir to the Bush organization.

But the weakness of the Baker campaign may be deeper than a slow start. The basic fact is that Baker feels comfortable as minority leader. He has a fallback position if he doesn't make it this time as presidential or vice presidential candidate. Almost alone among Republican candidates, he is young enough (53) and well-placed enough to lose in 1980 and come back in 1984.

It is notable that he lost races for the post of minority leader twice (in 1969 and 1971) before finally winning the job last year. That suggest not only that Baker doesn't make enemies, but that he is not a gut fighter, with the keen, even obsessive, appetite for the presidency that has been a critical element in the rise of all those who clawed their way to the job through the primaries.