Just a week ago until the 1980 presidential election, and suddenly the possible release of America's hostages in Iran is the biggest story in the news. The strong, familiar odor of politics fills the air, and suspicions are rife that the Carter White House has somehow cooked up this new hostage stew to create the "October surprise" that the Reagan camp has warned about for weeks.

In fact, though the evidence is strong that this latest excitement is more coincidence than diabolical design. Although the Carter administration certainly hopes it can turn these latest developments to political advantage -- and is trying hard to do so -- it is also afraid of negative political consequences that could accompany another round of dashed hopes.

What happened in the last few weeks to put the hostages crisis back at the center of the national consciousness just in time for the election? At least four different elements, including President Carter's own statements, explain this latest turn of events and also suggest its accidental character:

First and most important is the emergence of new attitudes in Tehran toward the hostages. A changed Iranian view was first signaled definitively by Ayatollah Ruhollah Khomeini on Sept. 12, when he gave a new list of four conditions that the United States would have to meet if the hostages were to be released. Khomeini's new conditions were softer than any previously enunciated, and only one of them -- the return of the shah's wealth to Iran -- seemed difficult for the United States to satisfy. The Carter administration -- and, he announced, Ronald Reagan -- appeared willing to guarantee non-interference in Iranian affairs, unfreeze Iranian assets in the United States and drop other financial claims against Iran, which were Khomeini's new conditions.

In the days that followed, a series of Iranian politicians, including many closely tied to the militant faction that had earlier opposed any release of the hostages, made new and conciliatory statements. And the Iranian parliament appointed a special committee to investigate the hostage issue that had the option of reporting its findings at any time.

Second and least predictable of all, Iraq decided in late September to launch an all-out war against Iran. The ultimate effects of this war are still uncertain, but it had the immediate consequences of rallying the Iranian nation behind President Abol Hassan Bani-Sadr (who has long favored releasing the hostages) and also reminding the Iranians vividly of their international isolation. Both factors enhanced the prospects for the hostages' release.

Iran's need for international support to end the war with Iraq on acceptable terms is probably the most important new element in the situation. As long as the American hostages remain in Tehran, Iran apparently has no real chance of significant international support, even in a war Iran clearly did not initiate.

The war has been a devastating blow to Iran's economy, creating unexpected and powerful new incentives for the Iranian authorities to seek to unfreeze the $8 billion of Iranian assets held by the United States and end international economic sanctions against Iran. The war also created a sudden new need for military supplies worth about $400 million that Iran has bought and paid for but remain in America warehouses pending resolution of the hostage crisis.

The third factor contributing to this latest round of hostage excitement is the behavior of the Carter administration and the public statements of the president. Only scant information is yet available, but the circumstantial evidence is powerful that the Carter administration has been engaged in intense new efforts to win the hostages release at least since Sept. 12, when Khomeini enunciated his new, milder conditions.

The first public sign of these new efforts was a secretive trip to Europe by Deputy Secretary of State Warren Christopher during the week of Sept. 14 On Sept. 16 President Carter made his first statement in this latest sequence of events, telling a town meeting in Houston that recent statements from Iran "may very well lead to a resolution" of the hostage crisis. Carter's own secretary of state immediately discouraged such optimism, but in retrospect it appears the president was guilty of more than a mistaken slip of the tongue. In the days that followed senior officials revealed privately that intense maneuvering was under way, though they also cautioned that the outcome was thoroughly uncertain. As this newspaper reported on Oct. 15, some officials by that date thought a break in the crisis might come within two or three weeks.

On that same day, the Carter administration abandoned the policy of "neutrality" it had adopted toward the Iran-Iraq war. On the campaign trail in Pennsylvania and New Jersey, Carter described Iraq as the aggressor in the war, a change that was clearly a signal to Tehran. The president also said: ". . . Perhaps since they [Iran] have a government and are in danger themselves, we have a better chance to get the hostages back now than before."

Two days later, Carter told the Associated Press in an interview, "I think it would be inappropriate now to build up expectations for a breakthrough on the hostages." Asked if he had any reason to think the hostages might be released by Election Day, Carter said, "No . . . I don't have any reason to predict that they will."

This one-two punch has been characteristic of the administration's public posture. Hints are offered, but then their implication is denied. In fact the Carter administration has not promised an early return of the hostages, nor has it denied that this might happen. The hope stays alive, but without specific official encouragement.

The fourth factor that has created the new excitement over the hostages is the unofficial encouragement the prospect of their release has received from the news media, which is ill equipped to deal dispassionately with a complex, emotional and largely unpredictable situation of this kind.

Any consumer of the television news over the last 10 days has seen at least one report on the imminent release of the hostages. Last Friday President Carter criticized the media for an unjustified "buildup of expectations" that the hostages would soon be freed, a story that made all the front pages.

Friday night the NBC Nightly News began with a film clip of Carter making this statement, then continued with a report from Bill McLaughlin at the United Nations. Quoting "a reliable and high-ranking Moslem diplomat" at the United Nations who McLaughlin said had been in direct contact with Iranian officials, the correspondent said that "barring unforeseen circumstances," the hostages would be released Sunday -- the day before yesterday.

The newspapers have made their special contribution, too, adding qualified but essentially encouraging reports. The Post reported on Friday that senior administration officials were "cautiously optimistic" that the hostages really would get out this time. Saturday The New York Times reported that the authorities in Tehran were actively considering the imminent release of at least some of the hostages. In a situation like this one, any story that doesn't refute the generally optimistic drift of the news tends to encourage it, as these stories showed.

Another factor is at work in this episode: the Reagan camp's longstanding warning that Carter would pull an October surprise to try to win the election. This was a suspicion, but also a shrewd piece of public relations, for it fed the notion that anything that happened to help Carter in the final stages of the campaign would be the result of political scheming by the president.

Now the Carter campaign has its own fears of an October surprise -- great expectations that the hostages are coming home that somehow get destroyed before Election Day.