Egyptian President Anwar Sadat, in the most massive crackdown on religious extremism and political opposition since he came to power 11 years ago, apparently acted to halt these trends perceived as potential threats to his regime.

Yet, the question being asked by political analysts here is whether he has overreacted to the problems besetting his rule and in the process tarnished his carefully nurtured image as the most democratic leader in the Arab world.

In the past four days, Sadat has arrested more than 1,500 persons, withdrawn state recognition of the head of the Coptic Church, dissolved 13 Moslem and Christian extremist groups, banned seven religious or political publications, transferred 67 journalists and 64 professors to other jobs and issued decrees tightening the laws on the formation and activities of parties.

All this, he told the nation in a three-hour speech last night, was done to protect social peace and national unity and put an end to the worsening sectarian strife afflicting this nation of 42 million people.

"No politics in religion and no religion in politics," Sadat repeated, hammering home what was perhaps the main theme of his speech before a special session of parliament and the Consultative Council.

The message in the state-controlled media is that Egypt must not become either another Lebanon, torn asunder by Moslem-Christian fighting, or another Iran, where the rule of Moslem fundamentalism has produced turmoil.

"Sadat does not want a second Lebanon or Iran here," said Coptic Bishop Samuel, who was appointed to the five-member commission announced last night by Sadat to run the church's affairs of state in place of Pope Shenouda III.

Interestingly, the same remark was made by a Moslem interviewed in the street who readily agreed with the sentiment, suggesting that the message is getting through and finding some support among Egyptians of both religions.

The question remains of how serious the menace from religious extremism or the political opposition is to Sadat's regime -- whether the measures he has taken, calling them a new "revolution," were warranted.

Heretofore, most Western diplomats have regarded his rule as relatively stable and unthreatened, despite bubblings of discontent from Moslem fundamentalists and leftist opposition elements.

To justify his measures, Sadat drew a disquieting picture of the state of his nation, arguing that religious extremism was getting out of hand and that the country was veering onto a dangerous course.

While he chastized Pope Shenouda and Christian extremist provocations, the thrust of his attack was aimed at discrediting the Moslem Brotherhood and the scores of Islamic fundamentalist groups that have sprung up here in the past decade, becoming increasingly critical of the Western and secular ways of Egyptian society and also of Sadat's policies.

Sadat drew a picture of them all working together to lead Egyptians astray, particularly the young, who he said were giving blind allegiance to such self-proclaimed prophets as Helmi Gazar, who calls himself "the emir of all emirs" and leads Islamic groups active on university campuses.

The president said he knew of 10 incidents where children had abandoned their families to join such Islamic groups and others where the emirs had taken another man's wife for their own.

Yet, in attempting to discredit these Moslem extremists, Sadat also indicated that their attacks on his policies and person irked him as much as their religious extremism.

He complained at length about the sermons of Sheik Ahmed Mehalawi, whose mosque is in Alexandria where Sadat spent most of the summer, and castigated the Moslem Brotherhood organ Al Daawa and its editor Omar Telmissani. All, he said, were echoing the attacks of his worst enemies -- Muammar Qaddafi of Libya and Ayatollah Ruhollah Khomeini of Iran -- on his peace treaty with Israel and alliance with the United States.

While Sadat singled out a number of his critics by name and read what they said about him, he did not present any evidence of a concerted conspiracy by the Moslem fundamentalist groups, or any other faction against his regime.

Sadat may have seen merit in moving before extremists became bolder and better organized. In addition, there were clear signs that the sectarian strife, which has taken at least 20 lives and wounded more than 100 in recent months, was getting out of hand.

But now Sadat has silenced practically every voice opposed to his policies and made it nearly impossible for public criticism to be aired. Calling such criticism "lies," "absolute impudence" and "insolence," he has said he intends to put all 1,536 persons arrested on trial for jeopardizing the security of the nation.

At the same time, he has said that he will not dissolve the presently legal opposition parties and that the trials will be open and fair.

While not abandoning the rule of law, Sadat has clearly narrowed considerably his notion of "democracy" and shown that his tolerance for real dissent has all but ended. This tough approach may reduce the overt sectarian strife, but it may also drive the religious and political extremists underground and lay the groundwork for another form of opposition much more difficult to cope with.