George Shultz for president?

Morris (Mo) Udall was talking about charisma the other day. He said that if the economy gets a little better it would take a Democrat with charisma to have a chance of beating the likable Mr. Reagan.

Charisma. It's that certain something that some politicians have, some don't. You don't have to have it to win. But it helps. Coolidge certainly didn't have it. Neither did Hoover. But that was before television, before people really got to know the candidates very well.

Eisenhower had a winning smile. So did Carter. FDR exuded hope. He fairly lit up the Pathe News screen, and his warmth came through clearly on radio. Now comes Ronald Reagan, perhaps the most personable of all the presidents. Certainly he is the most consistently friendly.

Of the current crop of Democratic candidates there is none with an overabundance of this indefinable but most valuable quality called charisma.

Kennedy has it - or many people think he does. Other Democrats have only a fair amount of personal appeal. Cranston and Glenn seem to have little at all. Mondale seems to be working hard at showing that he possesses this helpful political asset. Hart might have some of this ingredient. Hollings and Askew, too. And Udall's wit might make him the most appealing of the bunch.

But none of these Democrats, including Kennedy, is in the same class with Ronald Reagan when it comes to projecting a persuasive, likable image on the TV screen.

Alan Cranston acknowledges that some observers say he is colorless. Maybe, he told a breakfast meeting, people now were looking for substance and not appearance. ''Perhaps,'' he quipped, ''the voters now are looking for a candidate without much hair on his head.''

It may indeed be the moment in history for a presidential candidate with a little more subdued personality. Even Jimmy Carter suggested this the other morning when he remarked with a smile that the voters might choose John Glenn: ''Maybe after having had a born-again Baptist and a movie star the country is ready for something different.''

Glenn is the quiet-spoken candidate. He has been an astronaut hero, but he doesn't trade on the fact. He, like Truman, talks about the issues in a responsible but often not too interesting way. But, unlike Truman, he doesn't use angry rhetoric as a device to stir up support.

Without a microphone, Glenn cannot be heard much beyond the head table. He's clearly opposed to bombast. It's almost as if he were saying, ''I'm going to win you over by what I'm saying - and where I stand. And if I'm dull - well, that's just too bad.''

This approach enabled Glenn to win more than 70 percent of the vote in Ohio in 1980, while Reagan captured the state in the presidential race.

On the Republican side, there is the beginning of a boomlet for George Shultz for president. Not a Shultz challenge to Reagan of course. Only a bid for the White House if Reagan decided, for personal reasons, not to run again.

Shultz is the quiet man of this administration. On television he always looks a bit surprised. And then he utters a few rather uninteresting - but carefully chosen - words. And that's it. When it comes to charisma Shultz would likely finish below Glenn. Or Cranston. Or maybe even Coolidge.

But a growing number of influential Republicans are saying of a possible Shultz candidacy: ''What a great idea!'' Then they go on to say that maybe voters are indeed ready for a man with Shultz's impressive credentials: among them dean of the University of Chicago business school; secretary of labor and treasury and head of the Office of Management and Budget under Nixon; president of the Bechtel Group, Inc.; and now secretary of state.

Some TV people were discussing Shultz the other day: ''Funny thing,'' one said, ''but Shultz comes over well on television. He's low keyed. And he sometimes mutters. But people seem to like what they see. I think they like the fact that he is so modest - and just the opposite of Al Haig.''

Doubtless, we have a lot to learn about charisma. Maybe a new kind of charisma is emerging.