SOCIALISM AND AMERICA. By Irving Howe. Harcourt Brace Jovanovich. 225 pp. $17.95.

BEING A SOCIALIST in America today must be akin to being a pantheist in fifth-century Rome. There are holes in the temple roof and the janitor has gone off to get baptized. Irving Howe, a learned and wise man and a lifelong socialist, imports some of that feeling in his new book:

"Powerful parties in Europe still employ the socialist vocabulary, and millions of people still accept the socialist label, yet some deep inner crisis of belief, to say nothing of public failures and defeats, has beset socialism. The soaring passions of the early movement are gone, and those of us who strive for socialist renewal cannot help wondering whether we are caught in the drift of historical decline, perhaps beyond reversing, perhaps to yield at some future moment to a new radical humanism. . . . Nowhere on the globe can one point to a free, developed socialist society. The proclaimed goal has not been reached, and as I write, it does not seem close. Socialism has been shaken by failures, torn by doubts. Its language and symbols have been appropriated by parodic totalitarianism, and from this trauma we have still to recover."

A man of lesser consecration to his ideals might have bagged it, but Howe remains a socialist, a literate, humane one who has a keener understanding of socialism's problems than do socialism's opponents. Nevertheless the question which nags him is how did such a glorious idea come such a cropper in America? In this moment of consumerite degeneracy it may be obvious to us that socialism ab ovo was unsuited to American soil, but that was far less clear 75 years ago when the Socialist Party of America had many thousands of members, active chapters all over the country and was electing mayors to office from San Antonio, Texas, to Hartford, Connecticut. To many a worried conservative in the 1912 presidential election, when the Socialists garnered 6 percent of the vote it did not look like a party without a future.

Howe gives a number of reasons to explain what went wrong with socialism on these shores. All seem to have merit, but the most intriguing and most worldly is his discussion of our political culture. The people who conduct the opinion polls and interpret politics for us have a flat view of the stream of current events which seldom rises above formulations like: the employed vote Republican and the unemployed vote Democratic. The seat of civic consciousness, they tell us, is our gut, but Howe explains that even the practical-minded American has ideals and is influenced by them. However, it may take some looking to see this because, as he writes, "The distinctive American ideology takes on a decidedly nonideological mask."

THE WORD IDEOLOGY, at least on television, carries an exclusively pejorative meaning so that many of us are made uncomfortable when it is used as a descriptive term and applied to ourselves. Yet there has to be something more to our politics than the question, "Are you better off now than you were four years ago?" and Howe's calm prose enables us to dip into what that more might be with little pain and much persuasive analysis.

He also prowls around in the national myth, trying to see how what we believe about our origins and our history has made American ears deaf to the socialist message. In the course of doing so he drops little things about us that historians know but which they don't teach you in school. Thus in this year when the emphasis is on getting kids to donate their dimes to give the Statue of Liberty a facial, you can read in Howe's book that in the early years of the century almost 50 percent of the immigrants from southern and eastern Europe turned around and went home; over 70 percent of immigrants from Italy sailed back.

Howe doesn't drop these nuggets to shock but merely en passant in discussing the place that myths have had in forming American political outlooks -- myths about immigration, about the frontier, about many things. It's a good change from the unidimensional claptrap we ordinarily get, but, be warned, while Howe is a clear and economical writer, he does suppose this is not the first book his readers have cracked open. Recent college grads may have a little trouble with it, but if they hang in there and look up a few of the references, they may get a jot of what they say they prize -- a real learning experience. Older readers, more accustomed to the printed word, will find this essay into clear-sighted idealism may make them a little less suicidal on those days they fall sobbing onto their morning newspapers.