It would be highly unusual for a head of state in a situation as favorable as Mr. Kirchner’s to voluntarily relinquish office. The Argentine economy has grown by 8 percent or more every year since he took power in 2003, and largely as a result, two-thirds of Argentines approve of his job performance.

But the Kirchners seem to be playing for stakes much bigger than just the Oct. 28 election and the next four years, political analysts argue. Rather, their objective is said to be to take turns in office for at least the next dozen years.

Term limits in Argentina are in some respect similar to those in the United States, with one important difference. Presidents here are restricted to two consecutive four-year terms, but they are allowed to return after four years on the sidelines and run again — though no one has yet achieved that feat.

“If he were to be elected to a second term now, party discipline would break down and power would rapidly flow away from Kirchner,” said Joaquín Morales Solá, the chief political columnist of the conservative daily newspaper La Nación. “This is the form they have found to avoid a weakened second term for him: create the possibility of eight years of Cristina and then his return.”

The Peronist movement has a tradition, of course, of power couples that dates back 60 years, to Gen. Juan Domingo Perón and his wife Eva, the former actress who became the idol of Argentina’s poor “shirtless” masses. But political analysts suggest that a more appropriate analogy for the Kirchners may be that of Bill and Hillary Clinton.

Mrs. Kirchner, 54, a lawyer who has served in both houses of Congress, is not only one of her husband’s trusted advisers, but also perhaps the only one able to criticize him without suffering career consequences. A foreign visitor recalls being with the president in a meeting when Mrs. Kirchner called to reproach him for something he had said in public that day; Mr. Kirchner’s response was to listen quietly and dutifully concur.

At a Feb. 24 stadium rally in the suburbs of Buenos Aires, which Mrs. Kirchner did not attend, Peronist loyalists were certainly acting as if she were already their candidate. About 20,000 people carried banners with slogans like “With Cristina to victory” and “Cristina president, Kirchner leader.”

“We will have Cristina Kirchner as our standard-bearer, taking the oath of office as president on Dec. 10,” said Carlos Kunkel, a member of Congress and one of the speakers. “That is the will of all of us.”

Recent trips abroad by Mrs. Kirchner also suggest that she is being groomed to succeed her husband. She traveled with him to a meeting of the Mercosur trade group in Brazil in January, went on her own to Paris this month to meet with the prime minister and the two main presidential candidates there, and is reported to be planning a trip to the United States in April.

But there are also signs that some traditional segments of the Peronist movement, while willing to accept four more years of Mr. Kirchner, who is 57, are not happy at the prospect of Mrs. Kirchner as a substitute.

Eduardo Duhalde, the former president who handpicked Mr. Kirchner as his successor but has become one of his main critics, did not respond to requests for an interview, but has gone on record in the Argentine press with his objections.

“In general, I’ve never supported anybody without experience,” he told Clarín, a daily newspaper here in the capital. “I believe, as the Americans generally do, that in order to become president, you have to have administrative experience. And Cristina doesn’t have the administrative experience to be president.”

Polls consistently predict that Mrs. Kirchner would win about 10 percentage points less than her husband would in a presidential vote. His greater popularity could eventually prove important and force him to seek a second term. But at the moment, the opposition here is so fragmented and disorganized that only one candidate, Roberto Lavagna, a former minister of the economy, registers as even a possible threat.

“Right now, both are winners, though he is tougher to beat,” said Felipe Noguera, a political consultant and analyst here. “He has been a very successful president, but if you look around Latin America, second terms tend not to go that well.”

In addition, feigning indifference to the attractions of power enhances Mr. Kirchner’s popularity. “The life and history of a people don’t depend on an election,” he said recently in a speech.

Despite Mr. Kirchner’s popularity, there are risks to his strategy. The most obvious, economists and political analysts here say, is that the inflationary pressures he has largely kept in check with price controls and export taxes are building and could explode early in the next term, no matter which of the Kirchners became president.

“This is going to end badly, and everybody knows it, but when?” asked Rosendo Fraga, director of the Center for a New Majority, a political and military research company here. “In the meantime, the economy is piling up surpluses that allow the president to build his political power” through the traditional Peronist system of patronage and favors.

Early in February, the government was accused of manipulating the official inflation rate, after the official in charge of calculating the index was replaced. The official figure was 1.1 percent, but economists and stock market analysts, more than 200 of whom signed a statement saying that the changes in personnel and methodology “generate distrust,” maintain that the real rate may have been as much as twice that.

No one, except perhaps the Kirchners themselves, seems to know how long the waiting game over the presidential nominee will continue. By law, a final decision is not required until two months before the election, which gives Mr. Kirchner plenty of time to ratchet up the suspense.

“There is no need for him to define himself now, neither legally nor politically,” Mr. Fraga said. “To do so is to lose the freedom of action and maneuverability he cherishes.”