He holds that American public school children are “just as secularized” as those in the Soviet Union when it comes to religious instruction.

He believes that the only salvation for this country, which he maintains is “a long way down the road” to tyranny, is to return the nation, its laws and its government to its “Christian foundations.”

The views are those of Dr. Francis A. Schaeffer, a man regarded as a modern-day prophet by certain segments of conservative evangelical Christianity. Schaeffer, an American whose Swiss-based L’Abri center for the conversion of young people has spread its influence around the world, is not widely known in this country.

That may change. The jet-setting evangelist has canceled his commitments in other parts of the world to devote a year to what he views as the grave spiritual and political peril of this country.

Earlier this week, he brought the convention of the National Religious Broadcasters to its feet in shouts of approbation with his grim analysis of this nation’s moral climate and his challenge to the broadcasters to use their airwaves to set things right again.

In Schaeffer’s view, the great evil that has befallen this country in the last 40 to 80 years is secular humanism. In that time, he said, there has been “a shift from a Christian foundation to a humanistic one. Instead of the final reality being in a living, personal God . . . we are now taught in our public schools and in much of our media that instead of God, the final reality is material or energy shaped by chance.”

The secular humanist philosophy has not only given sanction to abortion, pornography, “the breakdown in the family, the killing of human babies,” it is also beginning to erode traditional freedoms in this country, he said.

“The founding fathers founded this country on the basis that there is a God, that He gave inalienable rights,” he said. As the humanist world view “takes over, these freedoms are going to be lost. There will be chaos because there is no absolute in humanism to which to appeal,” he said, which, in turn, “will lead to some form of authoritarian control to control the chaos.”

Schaeffer and his wife, Edith, have become almost cultic figures within a certain segment of conservative evangelicalism. Having lived most of his professional life in Switzerland, his influence in this country has been largely through his books and an occasional speaking engagement, though a vigorously antiabortion film, “Whatever Happened to the Human Race,” in which he appears with Surgeon General C. Everett Koop, brought him to the attention of TV audiences last year.

He has written 22 books that have been translated into 25 languages, according to the publisher of his latest work, “The Christian Manifesto.” There are 2 1/2 million copies of his works in English alone. One of his publishers is Inter-Varsity Press, which caters to evangelicals in the university communities.

He is no mass evangelist in the style of Billy Graham. Schaeffer’s efforts at soul-winning have been much more personal, particularly in the small groups that assemble and live for a time in his L’Abri community. In his early days as a pastor he allied himself with the International Council of Churches, now dominated by the fundamentalist preacher, Carl McIntire, but Schaeffer eventually broke with that group because he found it too antagonistic in its dealings with other Christians, and founded his own church at L’Abri.

Both his and his wife’s works are used widely as the basis for Christian cells and study groups within conservative evangelical circles. A thinker as well as a rousing preacher, he has become the leading theoretician for a substantial segment of born-again Protestantism.

Schaeffer is regarded by his admirers as an apostle to intellectuals, lecturing in university communities. But his current war on secular humanism may shift that focus. During much of the four days of the broadcasters’ convention here, he spent his time talking to and praying with an array of government officials “up to all but the highest level,” an aide said, pressing his view that a national return to God is the only salvation for the nation.

Schaeffer, who is given to quoting himself and the books and films of other members of his family in both his speeches and his books, issues his clarion call only to other born-again, “Bible-believing” Christians. Liberal Christianity, he says repeatedly, is only another part of the problem.

“The [Christian] liberals these days always come down on the side of the humanists,” he told the broadcasters.

Christians — “and I mean real Christians” — have been “stupid” and too much concerned with their own affairs in recent years to recognize the growing peril, Schaeffer said.

“If the church had been stirred 40 years ago even to the level it is today the country would not be in the mess it’s in,” he said.

The prime example of the humanist view, the Supreme Court’s ruling nine years ago on abortion, “had no basis in law,” he said. It cut “the law completely adrift not only from God’s law but from the Constitution as well.” He did not elaborate this point.

As for the banishment of religious instruction and exercises in public schools, “It’s tyranny! It’s tyranny!” he cried. “Congress opens with prayer, but children can’t pray in school.”

Schaeffer said that “in the conservative swing in the last election, we have a special opportunity . . . It’s now or never.”

In sanctioning abortion, pornography and euthanasia and in driving religion from the schools, “The government has made itself a false God,” Schaeffer thundered. “Are we to bow down to a false God?”

From the back of the hall came the cry: “Never!”

“You are the people,” Schaeffer told the broadcasters; “You are the ones who reach this nation . . . who have the technology to speak to people as no one else has . . . If you don’t carry this message, who is going to?” he challenged.

“We must use every legal means at the present time” to return the nation to its Judeo-Christian heritage, he said. But if persuasion fails, Christians “must face the bottom line and face what people in communist countries face” and break objectionable laws in civil disobedience.

After all, he said, “When a government negates the law of God, it abrogates its authority.”