The primaries?

A LOT of unfavorable things are being said these days about the system whereby the United States of America picks its presidents - and with reason. Not all of the recent choices have gone down in history as successful. Lyndon Johnson is remembered not for the good things he did, of which there were several, but for getting his country into its longest, and first unsuccessful, war.

Richard Nixon is remembered for Watergate.

Gerald Ford is remembered for pardoning Richard Nixon and failing to check inflation.

Jimmy Carter is remembered for a flawed act of compassion, allowing the Shah of Iran to enter the US for hospital treatment and thereby triggering the seizure of the US Embassy in Tehran.

And it begins to look more and more as if Ronald Reagan will be remembered for selling guns to Iran and handing over the profits from the deal to the contras in Nicaragua, in defiance of the expressed will of the Congress.

The Economist, in its May 9 issue, puts it (in my own opinion a shade too bluntly) as follows: ``America gets bad presidents because it gets bad candidates, and it gets bad candidates because they are now chosen chiefly in a series of primary elections in which voters put a premium on superficial qualities televisually conveyed, with little consideration of the attributes needed to run the most powerful country in the world.''

The presidents mentioned above, and in the Economist commentary, were not all bad. Each had good things to his credit. Each may do better on the pages of history than in current popular memory, but none is yet considered a major success and none is being compared with the greats of US history - Washington, Jefferson, Jackson, and Lincoln. Many would add both the Roosevelts and Eisenhower.

But the convention system, although it gave us Lincoln, the two Roosevelts, and Eisenhower, also gave us a string of non-memorable presidents and some who were worse. Warren Gamaliel Harding was a disaster. No one knows whether Calvin Coolidge might have been either a good or bad president. Nothing happened during his presidency to test his competence, or incompetence.

The same could be said of Harrison, Tyler, and Polk; of Taylor, Fillmore, and Pierce. Buchanan failed to head off the Civil War, while Hayes, Garfield, Arthur, and Benjamin Harrison left little on the pages of history.

All of which is why the US in this century has moved over by stages to the primary system, which by 1984 had become dominant. Since 1952, every major party nominee has been selected on the first ballot. The convention has merely ratified the selection by primaries that had preceded the convention. The primary system gave us Kennedy, Johnson, Nixon, Ford, Carter, and Reagan.

In Britain, most prime ministers of this century (Maggie Thatcher is an exception) served in the three most important Cabinet posts (Foreign Office, Home Office, and Treasury) before being considered ready for the top office.

In terms of similar high-level experience, Nixon was the best prepared US president of this century, which proves, what?

Has the primary system gone too far? It might easily have made Gary Hart the next president of the US. With his withdrawal (for reasons covered elsewhere), it seems likely to put Jesse Jackson in the front-running position in the Democratic Party - at least momentarily.

Recent experience would seem to indicate that the primary system has a tendency to send foreign policy innocents to Washington. Johnson, Carter, and Reagan came to grief over foreign policy.

Americans have yet to devise a political system that adequately trains its candidates for the presidency. Both convention and primary systems have turned up some successes and some disasters.