With the telephone call that awakened him in his Chicago hotel suite at 4 a.m., President Carter yesterday set in motion a carefully prearranged plan of operation that would carry him toward the most crucial decision of his uncertain political and presidential future.

In an hour and a half, in yesterday's predawn darkness, the president had dramatically departed Chicago's O'Hare airport, rousting his retinue of aides and taking them along with him as he flew to the White House for the first of a series of meetings. By 8 a.m., Carter was sitting in the Cabinet Room with his high echelon, deliberating on the proper response to the Iranian parliament's statement of conditions for the release of the American hostages -- a declaration apparently carefully timed by the Iranians for the Sunday before the president's political fate will be decided by the American people.

Jimmy Carter was already fighting for his political life, behind in the polls with 48 hours to go. Now he was confronting one of the trickiest diplomatic crises of his presidency. The Iranian leadership seemed to want it that way, perhaps in hopes of influencing the election results (they have spoken derogatorily about what a Reagan victory would mean) and more probably in the hopes of wringing greater concessions from a president who has been, for all the world to see, embattled.

It was evening when Carter finally strode into the White House press room, took his place behind the lectern, and looked the nation in the eye. "We are within two days of an important national election," he said. "Let me assure you that my decisions on this crucial matter will not be affected by the calendar."

His face showed weary signs of a long and difficult day. The president and his advisers had already received information through diplomatic channel as to which parts of the statement from Iran's parliament were considered vital, and which parts had been said "mostly for public consumption," in the words of one U.S. official. Now, the president told Americans that the latest statements from Iran appeared to offer a "positive basis" for ensuring a release of the hostages consistent with the protection of U.S. national interests and honor. And, in words aimed more to Iran than America, he added: ". . . whether our hostages come home before or after the election, and regardless of the outcome of the election, the Iranian government and the world community will find our country, its people, and the leaders of both political parties united in desiring the early and safe return of the hostages to their homes -- but only on a basis that preserves our national honor and our national integrity."

With that, the president turned to the right and left the press room, returning the national television audience to the football games they had been watching before his diplomatic interruption.

It had been a day in which the administration had endeavored to moderate expectations, even as it sought to frame a proper response to Iran. In midday, press secretary Jody Powell declared: "I think no one should for a moment labor under the misapprehension that the timing of the American election will in any way affect the position of the American government." How are the hostage deliberations being affected by the pressure of the upcoming election? "They aren't," Powell answered flatly at a news briefing attended by reporters who had left Chicago later in the morning in pursuit of the president.

But within the Carter White House, as well as outside it, the president's dilemma was that the hostage crisis could not be divorced from the president's political crisis. For, politically, many in the White House have come to feel, Carter has himself been held hostage by the leadership of Iran.

"No matter what we say, it will come down to the fact that we are damned if we do and we are damned if we don't," said one White House official. He was expressing a feeling of frustration and gloom that comes in the midst of this development in Tehran that could be the political salvation of the besieged Carter presidency.

Throughout these last days of the campaign at home and the ongoing crisis in Iran, the Carter officials had worried about the risks that would accompany any benefit of an American response to Iranian demands that had to be made on the eve of the election. Would Carter stand accused of having deliberately manipulated the crisis to a preelection climax? Would he stand accused of having either conceded too much or being too intransigent?

Yesterday, appearing on "Face the Nation" (CBS, WDVM), Ronald Reagan's vice presidential running mate, George Bush, spoke in understanding and even sympathetic terms of the problem Carter faced. Others in the Reagan stable, notably former president Ford and former secretary of state Henry Kissinger would be a bit less charitable in their comments during the day. But Bush declared: "I'm the first to admit this is not easy. The president has a very difficult problem here . . . I don't think the hostage thing is being manipulated by the president for political gain." He added that he did think that the timing was manipulated by the Iranians -- which is just what the Carter officials had been saying.

Days ago, anticipating a last-ditch move by the parliament in Iran that would come while Carter was on the campaign trail, the president and his advisers had worked out a plan of operation on how they would go about determining what their response would be. The president would immediately fly to Washington and do his deliberating at the White House, regardless of the campaign schedule and regardless of the importance of those campaign events that would have to be scrapped. The White House was a place where advisers could be readily at hand, where the best of communications were available. It was also a place where Carter's dilemma of policy and politics would be spotlighted for all to see, for whatever benefit or detriment that might bring.

When the parliament was readying for its final meeting that would come during the late hours of Saturday night in the United States, it was already considered likely by a number of American officials that a quorum would be on hand and that conditions would at last be approved. This may explain in large measure why Carter's chief campaign strategist, Hamilton Jordan (who has also done time as a backstage global intermediary during previous efforts to resolve the hostage crisis) left Washington Saturday evening and flew to Chicago to be with the president. His visit to that city proved rather brief. For at 5 a.m., Jordan was among those who Carter had rounded up to fly back to Washington aboard Air Force One.

At the White House, Carter convened at 8 a.m. with his advisers on policy, not politics, in a session around the Cabinet Room table. Attending were: Vice President Mondale (who would soon depart to take Carter's place on the campaign stops that had been scheduled for yesterday), Secretary of State Edmund S. Muskie (who would have to break away to appear on "Issues and Answers" (ABC, WJLA) at midday), Deputy Secretary of State Warren Christopher (who had drawn the assignment, at 4 a.m., of awakening the president in his suite on the 29th floor of the Hyatt Regency airport hotel in Chicago), Defense Secretary Harold Brown, national security adviser Zbigniew Brzezinski, Deputy Treasury Secretary Robert Carswell, counsel to the president Lloyd Cutler, and deputy national security adviser David Aaron.

The meeting recessed after two hours. And the president met again with his advisers in an hour-long session that began at 2 p.m.

Throughout the day, as the president pondered matters of hostage policy, other advisers were pondering matters of politics. The president's pollster, Patrick Caddell, was seen nervously pacing the corridors of the West Wing of the White House, moving from one conference to another. The president's closest friend and confidant, Atlanta attorney Charles Kirbo, was also present and conferring with others in the Carter inner circle. Late in the afternoon, a meeting of major political strategists was held in the office of White House chief of staff Jack Watson, with Caddell and campaign chairman Robert S. Strauss among those in attendance. c

Carter's political advisers remained concerned last night over whether even good news in the hostage crisis could offset the hard realities of the latest public polls.

"It is just too tough to call," said one of the president's top campaign advisers. "On the one hand, it is possible that there can be a positive impact politically where the president's policy of patience and persistence may be shown to have worked in Iran.

"But there is a down side, too. It may be that cynicism among the public will take hold and that people will come to believe that all of this was in fact engineered for political purposes. I hope that's not the way it turns out to be. But I just don't know."