UNTENDED GATES; The Mismanaged Press. By Norman E. Isaacs. Columbia University Press. 258 pp. $20; INVENTING REALITY; The Politics of the Mass Media. By Michael Parenti. St. Martin's Press. 258 pp. $16.95.

LET'S START with a statement on which we all can agree: The American press, print and broadcast, is not doing as good a job as it should be doing. Okay? Now a question: Where does the trouble lie?

I'm glad you asked. Here we have two attempts at an answer from two very different -- diametrically opposite, in fact -- sources. One, Norman Isaacs, is a distinguished journalist of the old school, almost in the guru class. The other, Michael Parenti, is an academic with a leftward tilt. They have drastically different views of the press. To Isaacs it is a fine institution that has gone astray; o Parenti it is a compliant tool of the power elite. Yet as they examine it their paths cross, and in the end they settle on the same villains -- media owners, money hungry to Isaacs and power protective to Parenti.

Isaacs never graduated from high school, but he was managing editor of the Indianapolis Times before he was 30, and he went on to be editor of four other papers and president- publisher of another. He has been chairman of the now defunct National News Council and an occasional teacher.

He sees deficiencies in the hiring and training of key personnel -- the "gatekeepers" who determine your daily news diet -- as the major cause of mediocre press performance. "The simple fact," he says, "is that much of the news content read in newspapers, heard on radio or delivered on television is controlled by men and women with limited perspectives of what is or is not 'news,' who for the most part have received no broad-gauged training, and who, when challenged, react with a defensiveness that astounds and infuriates outsiders."

The blame for this situation he places on profit-hungry owners of the media. "The root cause is schizophrenia -- the internal war between public purpose and making money." Money and the people who control and manage it are clearly the heart of the matter, in Isaacs' view. The "money market people," as he calls them, now play a major role in the media, he says, and they don't care "about how the newspapers, magazines and broadcasting stations they hustle to buy and sell handle news and editorial opinion." For them, he continues, "the business of communications is no different than dealing with automobiles, computers, food, toothpaste, shoes or anything else. . . . The one freedom that registers with them automatically is the freedom to make money in handling communications properties. There seems little point in raising the subject of journalistic obligations with them."

But, he warns, if those obligations aren't met, the press may suffer a dreadful comeuppance. He worries about increasing public hostility toward the press, as revealed in polls, and the possibility that a constitutional convention, probably called for a purpose having nothing to do with the press, would undertake a revision of the Bill of Rights, including the treasured First Amendment, which guarantees a free press. And getting back to his thesis, he asserts that unqualified executives who control the gates through which news reaches the public are mainly responsible for the slide in public confidence that might bring this about.

Despite his low opinion of the mass of media owners and managers, Isaacs feels that they are the key to a truly good and responsible press. He wants them to stop concentrating on profits and to pony up for "the employment and training of the most qualified men and women" for gatekeeping jobs. He wants a return to some basics that he feels are being neglected: Accuracy. Balance. Fairness. Compassion. Depth. Objectivity. Accountability. He wants a crackdown on the indiscriminate use of anonymous sources and an end to wolf- pack reporting. He would revive the national news council idea, and he urges more use of ombudsmen. That's all good stuff. But don't hold your breath.

PARENTI BRINGS a totally different approach; he views journalism from the outside. He has a PhD from Yale, has written several books, including Democracy for the Few and The Anti-Communist Impulse, and has taught. His publisher bills him as a major voice of the American left.

He sees a much broader and deeper problem than does Isaacs. In his view, the very foundation of what we call the free press is false. "We don't have a free and independent press in the United States but one that is tied by purchase and persuasion to wealthy elites and their government counterparts."

His mission here, he says, is to demonstrate that the "irreducible responsibility" of the press to this controlling elite "is to continually recreate a view of reality supportive of existing social and economic class power." In other words, while the media are allowed some leeway by their owners and on rare occasions break their bonds, their basic function, which colors all they do, is to support the establishment, the power structure.

To that end, says Parenti, the media present an invented reality, one that is skewed to the needs and beliefs of the ruling elite, which means to the right. He charges that the press favors management over labor, corporations over their opponents, the affluent over the poor, private enterprise over socialism, whites over blacks, men over women, officialdom over protesters, conventional politics over dissidence, anticommunism and the arms race over disarmament, national chauvinism over internationalism, U.S. dominance in the Third World over revolutionary change. His book is almost entirely devoted to his documentation of these charges.

There is a political heart to his argument, and he gets to it when he asks: "What is it about the dynamics of newsgathering and the foibles of reporters that obliges the press to treat capitalism as a benigh system and socialism as a pernicious one?" "Not much," he answers. "But there is plenty to explain that bias in the pattern of ownership and control, the vested class interests, the financial muscle of big advertisers and the entire capitalistic social and cultural order."

Parenti doesn't offer a prescription. Indeed, so deepseated is the disease he has diagnosed that it is hard to imagine a cure short of revolution. In his last few paragraphs, though, he offers hope of a sort. The controlling elite faces a danger, he says, when it insists that the press is free and independent. The danger is that "it (the press) may feel pressured -- both by the public and from within its own ranks -- to act that way at inconvenient times."

SO THERE YOU have it. An insider and an outsider, both serious and intelligent men, expressing deep concerns about an institution vital to the operation of the American democracy. Occasionally their paths converge. Each invokes a famous comment by that premier press critic, the late A.J. Liebling: "Freedom of the press is guaranteed only to those who own one." Isaacs uses it in attacking those who see the press as a money machine. Parenti uses it to reinforce his image of the media firmly in the grasp of a conspiracy of rightists. In the same vein, they both are concerned, as Liebling was 25 and more years ago, about the growing concentration of media control in the hands of a few huge corporations.

Both books have weaknesses. Isaacs is discursive and heavy on anecdotes, reminiscences and rehashings. And his prescription seems to rely heavily on a sort of spiritual awakening in people he portrays as quite satisfied with things as they are. Parenti has assembled an impressive mass of circumstantial evidence, but in the end he has invented a reality of conspiracy and suppression at least as contrary to real reality as the one he accuses the media of inventing.

Nevertheless, since Liebling is long gone and no press critic with his perception and bite has picked up his mantle, these vastly different yet complementary critiques of our ever-wayward press are recommended, as a pair, to both purveyors and consumers of news.