IN Sen. Goldwater's 1964 losing campaign, an ex-New Dealer and former president of the Screen Actors Guild emerged as an effective Goldwater surrogate and won for himself a following. It has remained to this day the real base of Ronald Reagan's constituency in California and the country. Now, 16 years later and six years after leaving the governor's office in Sacramento, Mr. Reagan has succeeded in beating the face cards of the Republican Party and in winning his party's presidential nomination in impressive fashion and with an apparent absence of any serious party bitterness. Mr. Reagan's victories in 20 of the 24 primaries he entered before he was left with the field to himself constituted a rout.

Early and quite easily, he defeated both Sen. Howard Baker and former Texas governor John Connally, two political heavyweights expected to make much better showings. The strength of the Reagan appeal was sufficiently impressive by then to discourage any late entry by former president Gerald Ford and, if not for the tenacity and resiliency of George Bush and his campaign, Mr. Reagan would have wrapped up the nomination by the first week of April.

For 16 years, Ronald Reagan has been a forceful and consistent spokesman for a political point of view peculiarly his own -- but one that was adopted, at least in part, by almost all his Republican opponents this year. Mr. Reagan has regularly called for cutting the size, scope and spending of the federal government. He has advocated both a more muscular defense policy and a more skeptical approach toward the Soviets. As anyone can see, Mr. Reagan's point of view has recently won at least a few adherents in the Opposition Party as well.

In the seven months since his announcement of candidacy, the former California governor seems effectively to have disposed of the age issue that was supposed to be such a problem for him in contending with his younger primary opponents. He has been an active and friendly campaigner. Mr. Reagan may even represent an entirely previously unsighted species of American political life: the affable ideologue.

American politics, which is not usually very ideological, has still had more than a few ideologues seek the presidency. In almost every case, these have been candidates without humor, warmth or an awful lot of personality. There may be some real argument about whether Mr. Reagan's public positions on issues like taxes, energy and foreign policy add up to a consistent or politically plausible alternative to the Democrats. But there really can be little question that in this campaign, especially in the televised debates, Mr. Reagan has been transformed for many voters from a fringe figure with a lot of rigid, outmoted views to a non-threatening and engaging human being.

There can also be little question -- given the current political woes of Jimmy Carter -- that Mr. Reagan has been transformed into a candidate who seems to have a chance.

So as the first real full five-month presidential campaign heaves into view, people will be listening to him with both a new awe and a new anxiety. This is the most delicate time yet for Mr. Reagan.