The boil was not lanced in Tehran. But the failure of the rescue mission has opened up a new phase in the presidency of Jimmy Carter and perhaps in U.S. foreign policy, almost as certainly as it would have if the raid had succeeded.

The president, faced with the raid's failure and operating from an already weakened political position, has chosen to break his promise not to campaign as long as the hostages are held prisoner.

Now he will take his case to the country, hoping to make political capital of the boldness, if not the results, of his rescue efforts.

It is clear many influential figures in Washington are deeply worried by the rescue effort and its aftermath.

Yet some fears are mitigated by a hope that the president can get back on a course that is not dominated by the hostage issue.

Sen. Henry M. Jackson (D-Wash.), for example, says the president has done the "sensible" thing in dropping his Rose Garden strategy and that it should have been dropped a lot sooner.

But Jackson also coupled this with a sharp warning to the president to break his and the national obsession with the hostages. Carter, he said, must shift his focus from that narrow and emotional issue, and from military solutions, to the broader and more crucial matters of overall U.S. foreign and economic policy.

Furthermore, the conservative Democrat who carries a lot of weight at the Pentagon, also sharply warned the president against taking additional military action to try and solve the hostage crisis.

"I violently oppose" any such plans, he told reporters. "Born-again hawks scare me," a possible reference to a president who -- in the aftermath of Iran and Afghanistan -- has shifted from the attitude of always forgoing the use of force.

In recent months, Jackson has repeatedly said he was afraid of "the hawks" and hardliners who may be too anxious to fight a war in a region near the Soviet Union which the United States is in no position to win at this time. Indeed, many senior military leaders say the same thing privately.

"Clearly we should turn to quiet diplomacy and not let ourselves be diverted on the central issue, which is the survival of Iran as an independent state, regardless of our feelings and emotions," the senator argues.

Middle East stability must be the number one U.S. foreign policy objective for the rest of this year, he says. Letting the "radicals and mad dogs" in Tehran whiplash the U.S. morning, noon and night does irreparable harm to U.S. foreign policy and plays into the hands of the Soviets, he argues, who are quietly working to take over Iran and thus eventually neutralize the oil-producing countries of the Persian Gulf.

America's allies are also nervous that there may be more military action in the offing from a still-narrowly focused White House. Though part of the rescue cover meant deceiving them, the allies are swallowing their chagrin and are rallying around the president's call for sanctions as another way hopefully to avoid military action.

As the man who takes responsibility for the aborted raid, its aftermath is most important for the president. His presidency is at risk, his statesmanship and helmsmanship in question. He has chosen to respond by returning to the active political fray.

There is no indication that Carter will defend the rescue operation on the grounds which actually prompted him to launch it -- a desire to "lance the boil," as one aide put it, or end the crisis once and for all, whether or not all the hostages could be saved. Instead Carter argues that the United States had a duty to do something after all diplomatic efforts had failed.

The decision to campaign again was prompted by more than calculations about the repercussions of the raid.

"There's going to be a lot coming out in the weeks ahead," a senior White House official said last week, "a lot of bad news about the recession and unemployment and things that the president has to be able to address. If we want to take what's going to come out head-on, the president is the only one who can do it."

This same official acknowleded that Carter's initial decision not to campaign while the hostages were held was partly political. He said, "We probably could have campaigned through a couple or three weeks of January, perhaps into February," he said, referring to the period in the hostage crisis before intense bargaining with the Iranian authorities began.

This meant, a questioner noted, that Carter could have joined the debate in Iowa Jan. 7 with Edmund G. (Jerry) Brown Jr. and Edward M. Kennedy, which the president dropped out of on Dec. 28, saying he needed to "preserve national unity on a non-partisan basis" in the hostage crisis.

The senior White House official did not dispute that assertion.

On the record, Carter explained his situation differently. One Feb. 13, for example, he said: "I want the world to know that I am not going to resume business as usual as a partisan campaigner out on the campaign trail until our hostages are back here, free and at home."

Now Carter is encumbered with another awkward explanation -- his version of why he can resume campaigning. On Wednesday Carter told civic leaders in the White House that the problems he faces as president "are manageable enough now for me to leave the White House for a limited travel schedule," as though somehow the failure of the rescue mission had already lessened his and the country's problems.

That could, of course, eventually be true, providing an ironic smell of success to the failed mission.

The abort has contributed to the president's decision to come out of the White House, a fact that will probably force greater presidential focus on such things as domestic economic woes.

Similarly, it may diminish the political pressure the president felt to "do something" about the hostages.