Last month, a U.S. District Court judge in Washington blocked the Carter administration's crackdown on Iranian students in the United States. To single them out for deporation would set a precedent, Judge Joyce Green ruled, which could usher in "future extreme assertions of executive power."

A month before that decision a different judge on the same court told President Carter that he did not have the power, on his own, to terminate the U.S. treaty with Taiwan.

Yet another D.C. District Court judge, five months earlier, removed the teeth from Carter's wage-price guidelines.

These decisions were all reversed by the U.S. Court of Appeals in the District. They may have turned in the first place on the individual quirks of individual judges in individual and very different cases. But many lawyers believe a pattern may be emerging in the lower courts.

The inspiration seems unmistakable: Many judges, especially since Watergate, have a new view of the presidency and the president. He is "an elected chief executive of our government," in the words of Chief U.S. Appeals Court Judge J. Skelly Wright, "not an omniscient leader cloaked in mystical powers."

In July, the appeals court put its own teeth into that doctrine. It ruled in the Morton Halperin wiretap case that a president could be held personally liable for damage claims. It was the first time that had happened, say Justice Department lawyers. It has left the executive branch openly and deeply distrubed and asking the Supreme Court to protect the president with a grant of absolute civil immunity from damages.

A turning point for these new attitudes, some lawyers believe, was the Supreme Court's decision in the Nixon tapes case which reaffirmed that the judiciary, not the president, says what the law is. That was a signal, says Bruce Fein, a Supreme Court expert for the American Enterprise Institue, both for judges and for the people who are now bringing cases before the courts they might not have otherwise.

"They are taking their lead from U.S. v. Nixon," said Fein. "The Supreme Court gave a signal to all the courts to consider cases [of presidential power] on the merits. There is no longer any reservation in the district courts about the presidency."

"Yes, I think that's true," said U.S. District Court Judge Oliver Gasch, who decided the Taiwan treaty case, when asked if he may have been emboldened by the tapes decision. "It may very well have been. I felt the issues should be met," he said.As a judge, "I felt this was my problem."

Others, like Yale Law School professor Robert Bork, a former U.S. solicitor general, see it as part of a much larger pattern. "It's part of the explosion of judicial power we saw with the Warren Court, part of a general judicial expansion. With the presidency, they hesitated a bit longer but they apparently aren't hesitating any more."

The change is most pronounced in the cases relating to a once sacred territory reserved for the president and Congress: foreign policy.

"That is their business not ours," said Justice Felix Frankfurter 35 years ago as he registered his approval of a Supreme Court decision allowing Japanese-American citizens to be shipped inland for internment during World War II.

These matters, the Supreme Court said again in 1952, "are so exclusively entrusted to the political branches of government as to be largely immune from judicial inquiry or interference."

The 1952 case, involving the deportation of resident aliens because of their past or present communist affiliations, was strikingly similar to the recent move against Iranian students. But the judicial response, at least at the first level, was strikingly dissimilar, and the Irnaian ruling caught government attorneys by surprise.

U.S. District Court Judge Green, the newest member of the court, stepped squarely into the controversy and ruled that the administration had no authority to single out Iranian students for possible deportation. It was, she said, unconstitutional.

Similarly, Judge Gasch saw no reason to stay out of the foreign policy controversy over the Carter administration's termination of the U.S. treaty with Taiwan and, in fact, ruled against Carter's action, saying that congressional approval was required for treaty termination.

Green's decision was promptly overturned by the U.S. Court of Appeals, which found the federal immigration laws authorized Carter's action so long as it was based on rational policy reasons.

The court, in a ruling by three of its more conservative members, also signaled its displeasure with the district court's incursion into foreign policy, underlining the traditional judicial approach.

"Certainly in a case such as the one presented here it is not the business of the courts to pass judgment on the decisions of the president in the field of foreign policy," said Judge Roger Robb, who was joined by Judges Edward Tamm and George MacKinnon. "Judges are not expert in that field and they lack the information necessary for the formation of an opinion."

Gasch's ruling on Taiwan also was overturned. But the Supreme Court, in its first response to these recent judicial assertions, was strangely mixed in its reaction as it ordered dismissal of the suit brought by Sen. Barry Goldwater (R.-Ariz) and others.

Chief Justice Warren Burger along with Justices William Rehnquist, Potter Stewart and John Paul Stevens, explaining their reasoning, said the case never should have been heard in the first place, in part because "it involves the authority of the president in the conduct of our country's foreign relations."

But justices Harry Blackmun, Byron R. White, William Brennan and Lewis F. Powell expressed no such opinion. The case does not entail an "impermissible interence in the field of foreign affairs," Powell wrote. It is a mistake, he said, quoting previous court decisions, "'to support that every case or controversy which touches foreign relations lies beyond judicial reach.'"

In the view of some legal scholars, it was the Burger court itself, however, that set the tone for what is now beginning to happen in the lower courts when it reasserted the courts' role as guardian against presidential abuse during Watergate. The same tone runs through most of the new decisions.

Gasch saw himself righting an imbalance of power and resotring an important check on the president. "A judicial determination that the president enjoys unilateral authority to terminate treaties would raise the same fears and present the same possibility of abuse" as any other case involving "unchecked power," Gasch wrote.

Green wrote that "to countenance the disparate treatment of Iranian students that this regulation candidly promotes would not only reject the most cherished constitutional precepts applicable to all of us, citizen and alien alike, but would create a precedent of alarming elasticity from which future extreme assertions of executive power could readily springboard."

And the court of appeals, in the Halperin case, said that "a proper regard for separation of powers does not require that the courts meekly avert their eyes from presidential excesses while invoking a sterile view of three branches of government entirely insulated from each other.

"Such an abdication of the judicial role would sap the vitality of the constitutional rights whose protection is entrusted to the judiciary."