As the presidential candidates stagger through the last of the 1980 primaries, it is well to ask whether the gauntlet we have erected is the best way to choose the Democratic and Republican nominees. The 37 primaries held this year (up from 16 in 1968) are a campaign manager's nightmare. No candidate can do justice to a primary campaign in which he must spread his time, organization and money over so many elections in such a short period of time.

In the spring of 1968 the late Sen. Robert Kennedy spent 25 days campaigning in Indiana, about the time it takes to stump a state of five million people. This year, his brother Edward spent less than two days there. Some primary states were lucky to see the candidates once. Two years ago, William Clements laid out $3.5 million to win the governorship of Texas. The amount President Carter spent to win this year's Texas primary -- $105,000 -- was less than it costs to air one 60-second commercial on prime-time network television. Indeed, the networks have spent more to cover this year's primaries than the candidates have to win them.

The candidates' field organizations are paper thin. A political mechanic from the candidate's national staff is dispatched to "do," as they say, Pennsylvania. The best he can do is to lay his hands on the state's political machinery and hope for the best. He sets up a headquarters in some seedy downtown building, gives interviews to reporters, tries to get local politicians who have endorsed his candidate to do some work for him, ends up spending most of his time pleading with his superiors for more television money and more of the candidate's time in the state.

Into the organizational vacuum come the single-interest groups. Forty percent of the Democratic delegates elected in Oklahoma this year are members of the National Education Association. The Democratic delegation from Manhattan, formerly known as Tammany Hall, is packed with advocates of gay rights. What would Boss Tweed think?

What we have created, withour realizing it, is a national primary that unfolds in weekly stages. Voters judge candidates by the impression they give on the network television news, which reaches far more people than the candidates' campaigns and is much more credible than paid political announcements. President Carter has shown that you don't have to campaign at all if you have assured access to the news and can perform a sufficient number of symbolic acts tied to the public's concern of the moment. Visit the wounded from the rescue team to Iran. Meet with the Olympic athletes. Fly over Mount St. Helens. Our system of choosing nominees offers an almost insuperable advantage to an incumbent president with resourceful press agents.

Some observers have suggested we return to the old system, in effect until 1964, where political leaders selected most of the delegates and where primaries -- there were just a handful -- were important only in showing the leaders which candidate was most popular with the voters. But our political development is beyond that now. Voters want, and have a right, to participate in the nominating process.

A national primary, in which everyone could vote on the same day, would best reflect today's political realities. It may be too abrupt a change, however, and it could dispose the candidates to emphasize the voters and problems of the heavily populated states at the expense of the others. The best solution for now is to consolidate the existing primaries into a series of five regional primaries, held a month apart between February and June. Each region would be anchored by at least one state with a large bloc of delegates, such as California in the western region and New York and Pennsylvania in the Northeast.

Under this plan, the critical first verdict -- the one that means momentum and money -- would be rendered by 10 states instead of one. If more voters felt the result in their state made a difference, participation would increase. fCandidates would have time to rest and regroup their forces before facing the next election. They could save funds by using media that cross state boundaries. They would no longer have to fly incessantly from East Coast to West and from warm climes to cold, a form of candidate torture that leaves them looking, and sometimes acting, like zombies. c

Regional primaries would not cure all the ills that have made our present system so listless. They might not even change the results. But they would be a better use of scarce campaign resources, and might bring some degree of sense into a system that has badly lost its way.