IN THE YEARS SINCE the assassinations of President Kennedy, Martin Luther King and Robert Kennedy, fear of the assassin has come to haunt our public life. From the first presidential primaries onward, the Secret Service agent is a prominent fixture on today's political scene. In 1963 the Secret Service had 450 agents and an annual budget of $5.8 million. In the current fiscal year, the Secret Service has 1,650 agents and a budget of $115 million. Any earlier chance of restraining that trend was severely damaged last year by two attempts on the life of President Ford. All the same, there are good reasons for the new Congress and the Carter administration to take a hard look at the costs and consequences of trying to assure the absolute personal security of our most important and conspicuous public figures.

Until 1963, the Secret Service's personal protection was accorded the President and the Vice President. And that was it. Today, by various acts of Congress, the Secret Service also protects former presidents and their wives for life; the widows of presidents for life unless they remarry; the minor children of former presidents until age 16; all "major candidates for the presidency; Secretary of State Henry A. Kissinger; Secretary of the Treasury William Simon; visiting heads of state or government; other foreign dignitaries designated for such protection by the President, and the persons and families of the President and Vice President. That is a large part of the reason for a 20-fold increase in the agency's budget in the years since the tragedy in Dallas. Each assassination or assassination attempt has stirred the same reflexive response from the Congress. It takes the form of a question to the Secret Service: Do you need any more money or authority?

Interestingly enough, the initiative has not come from the Secret Service. On the contrary, the Secret Service itself has been concerned about the rate at which Congress has expanded its assignments. The service is understandably worried about becoming a personal security agency, which it traditionally has not been, instead of a law enforcement agency, which is how it prefers to see itself. Before 1963, only 35 per cent of the Secret Service's business concerned personal security; 65 per cent of its effort went into tracking down counterfeiters and forgers of government checks and bonds. Today the figures are reversed, and the Secret Service is beginning to worry about its image. The more it looks like a personal security agency, instead of an investigative agency, the less able it may be in time to attract the first-class law enforcers who helped to give the agency its reputation.

Ironically, it is that reputation for crisp efficiency that has increased the demand for the agency's protective services. Mr. Kissinger, for one, had the choice of using the personnel of the State Department after he became Secretary of State, but he elected to maintain the Secret Service coverage he had received at the White House. That same factor - efficiency - helps explain the popularity of the Secret Service with presidential candidates last year. As any of those candidates will readily concede, a measure of order and an aura of importance were added to their campaigns when the Secret Service came aboard. One candidate noted that the advance work on his campaign left a great deal to be desired until the Sercet Service brought its technology to bear. Among other things, the Secret Service makes certain, for its own reasons, that the campaign runs on schedule. In effect, then, Secret Service coverage is a hidden, tax-supported subsidy for presidential candidates.

The monetary costs aside, another price paid for all this security is its transforming impact on our public life. For one thing, we are in danger of measuring the importance of public officials by the size of their bodyguards. For another, the proliferation of earplugged, flinty-eyed agents, walkie-talkies in hand, is not doing a thing for the appearance of American officialdom. To put it bluntly, we are acquiring, as our leaders parade about in public, the look of a police state.

How much real protection does all this security buy? Not much, judging from the record. Secret Service protection may make assassination more difficult and more dangerous for the assassin. But it is tragically self-evident that there is no guaranteed way to shield Presidents, candidates or any other public officials when they are exposed to crowds - as witness Dallas, the disabling of George Wallace, or the more recent near-miss attempts on the life of President Ford. If Lynette Fromme had been more proficient with a 45, President Ford would have been in mortal danger before his protectors could have reacted. Sara Jane Moore's aim was spoiled by an alert citizen, not a Secret Service agent.

To be fair about it, we have no way of measuring how many possible attacks have been frustrated by the service, or deterred by public knowledge that the agents are on guard. Even so, theissue is not whether some security precautions are necessary. Obviously some protection is needed for some of our most visible and exposed officials. The question, however, is whether Secret Service protection is not being way overdone. Without some serious thought, the trend of the last decade is likely to continue, with the result that more and more officials will be travelling about in a phalanx of police officers. It is not just a problem for the President or for Congress, for it is not easy for either one to strip away protection that has become an accepted fact of life - unless high officials themselves are prepared to share the responsibility and accept some reasonable level of risk as an inevitable part of the price of participating in public life.

To keep Secret Service agents from becoming status symbols or campaign aides, it seems to us that a new set of guidelines is in order. Their shape will depend on the level of threat as it is perceived by the responsible leaders of Congress and the executive branch. For instanct, it might be possible to eliminate, or at least reduce, the coverage of foreign dignitaries, as opposed to visiting heads of state: cabinet officials, unless there is a substantial justification: and the minor children of former presidents, unless there is exceptional evidence of danger. In the case of former presidents and their wives, it might be justifiable to provide coverage for several years but not for life. We would not pretend to know exactly where to draw the line. Nor is it possible for us, or anybody not privy to the facts of a particular case, to know when situations call for extraordinary precautions. As a general rule, however, it seems to us that excessive, highly visible security measures may be as likely to challenge the psychopathic impulses of a potential assassin as to deter them.

It ought to be obvious by now that there is no such thing as guranteed, foolproof security. It also seems obvious, at least to us, that the effort to achieve it - to put the best face on what now seems to be going on - has gotten out of hand. To put the worst face on it, what may be happening is the creation of yet another status symbol for those who hold or have held power. To the extent that this is what, in fact, is going on, it is perhaps worth remembering, in this time of transition and rich promises of reform, that the personal security mission of the Secret Service is to provide protection, within reason, and not to adorn.