HARARE, Zimbabwe » As Zimbabwe hurtles into another violent political season, President Robert Mugabe’s party is fiercely pushing for a quick election this year because of fears that the president’s health and vigor are rapidly ebbing, senior party officials said.

With no credible successor to unite the quarrelsome factions that threaten to splinter the party, its officials say they need Mugabe, who at 87 has been in power for 31 years, to campaign for yet another five-year term while he still has the strength for a rematch against his established rival, Prime Minister Morgan Tsvangirai, 59.

"There’s urgency, real urgency," said a party insider, speaking anonymously because of the delicacy of the topic. "The old man is not the same as he was."

Zimbabwe’s neighbors, who helped broker a power-sharing government led by Mugabe and Tsvangirai after a discredited election in 2008, have strongly warned against trying to hold another one too soon. But a separate Mugabe confidant said the party’s power brokers worried that the president would no longer be a plausible candidate by next year.

"Imagine him being supported all the way to the podium to address a rally and him telling the people he is the future of this country," the Mugabe confidant said. "Even the staunch supporters would not believe that."

The intensity of the party’s determination to hold an election this year was evident as a newspaper controlled by Mugabe’s party carried out an extraordinary attack on South Africa’s president, Jacob Zuma, the official mediator in Zimbabwe’s political crisis, after he publicly called for a halt to political violence in the country.

South Africa had long been criticized for coddling Mugabe through a decade of rigged, bloodstained elections, but last week Zuma persuaded regional leaders to endorse assertive, time-consuming efforts to ensure that the next time Zimbabweans voted, they would be able to do so freely and fairly.

"There is no way we can agree to an election in Zimbabwe when the institutions needed to ensure a credible, free and fair election are not in place," Zuma told Mugabe and Tsvangirai at the meeting, according to Zuma’s adviser, Lindiwe Zulu.

A day later, Mugabe defiantly told his party’s central committee that Zimbabwe’s neighbors should not meddle in its political affairs and urged his followers to prepare for an election. An editorial in the Sunday Mail, a state-controlled newspaper, accused Zuma of duplicity and dishonesty and called him a puppet of the West.

South African officials reacted sharply to the vitriolic, personal attack on the president of the region’s most powerful nation, and Mugabe’s spokesman this week sought to soften Zimbabwe’s tone, saying the editorial was not government policy.

"President Jacob Zuma’s erratic behavior is the stuff of legend," one of Mugabe’s loyalists wrote in the editorial’s opening line.

Mugabe’s domineering rule has led to the country’s disastrous economic decline, pervasive corruption and an intensely repressive society, but as the centerpiece of the state, there is uncertainty about whether his death would lead to a military coup, a vicious internal battle within his party, ZANU-PF, or some still unforeseen outcome.

"Mugabe’s health is a matter of national instability," Tsvangirai said. Having been pressured by regional leaders into the power-sharing deal with Mugabe, his political enemy, two years ago, Tsvangirai said of his still dominant partner, "He left the succession way too late, and now there is a scramble between the two main factions of ZANU-PF."

A Western ambassador here likened this period in one of Africa’s longest-surviving autocracies to the last days of Brezhnev and Franco. It is a time of fevered rumors and back-room plotting.

And it has brought a crackdown on pro-democracy civic groups and members of Tsvangirai’s party, the Movement for Democratic Change. The authorities have banned its rallies, rounded up activists and party workers and put truckloads of riot police officers on the streets to head off protests.

The revolutions in North Africa, and particularly South Africa’s support for a no-fly zone in Libya, have unnerved the sprawling spy operation controlled by Mugabe’s party. Dozens of students, trade unionists and activists who had gathered to watch news reports on the uprisings in Tunisia and Egypt were arrested in February and charged with treason, accused of plotting to oust Mugabe.

"We are hearing from the intelligence services that MDC meetings are intended to incite people to engage in an Egyptian-, Tunisian-style uprising," said a spokesman for Mugabe’s party, Rugare Gumbo.

Beyond that, recurrent speculation that Mugabe suffers from prostate cancer has quickened since he made trips to Singapore in February and March, ostensibly for routine follow-up care after cataract surgery he had there over the Christmas holidays. But, analysts here asked, why would such an elderly man have made three grueling, transoceanic flights unless he was really sick?

Cabinet ministers say Mugabe is mentally sharp but tires easily and has difficulty walking up stairs. Mugabe himself declared at his 87th birthday celebration in February, according to an Associated Press account, "My body may get spent, but I wish my mind will always be with you."

At a conference here in November, Mugabe was natty in a charcoal gray suit, blue silk tie and matching handkerchief peeking from his breast pocket. A waiter in white gloves poured his juice and hovered nearby. The president’s sonorous voice still echoed in the hall as he read a speech he held up close to his eyes.

But as he left the stage, Mugabe — his days as a vibrant liberation leader long past — gripped the banister as he slowly made his way down the steps. Outside, an ambulance trailed his limousine.

His press secretary, George Charamba, said at the time that Mugabe had dashed up 22 flights of stairs when elevators at the party headquarters malfunctioned, leaving security agents panting in his wake. Even some political opponents wonder if he has years left. His mother lived to nearly 100.

"There’s nothing that tells me he’s about to drop dead," said Theresa Makone, a leader of Tsvangirai’s party and the co-minister of Home Affairs in the power-sharing government.

But the uncertainty about his health has profoundly unsettled politics here.

After each of Mugabe’s Singapore trips, Charamba insisted in interviews that his boss had just been seeking routine eye care. But the spokesman revised that explanation in a recent interview, saying the president had actually made the trips to accompany his wife, Grace, who had badly injured her back while exercising at a gym.

"She’s up and about so we can talk about it" now, he said.

In a rare interview with Reuters last year, Mugabe himself brushed off rumors he was dying of cancer.

"I don’t know how many times I die, but nobody has ever talked about my resurrection," he said.

"Jesus died once, and resurrected only once, and poor Mugabe several times," the president added, laughing gleefully at his own joke.

Under the current constitution, if Mugabe died in office, ZANU-PF would choose the next president to finish out his term, legal experts said. Zimbabweans are supposed to vote on a new constitution before the next election, but drafting one has spurred an intense struggle between the parties. The member of Parliament leading the constitution-making effort for Tsvangirai’s party was recently jailed for almost a month.

Mugabe wants an election as soon as possible, not because of his own ill health, but because the power-sharing government is not working, his spokesman said.

Mugabe has unhappily shared the stage with Tsvangirai in what they call an inclusive government for the past two years. The deal has brought a tenuous political stability and improving economy, but has left Tsvangirai with little authority.

It was formed after the 2008 election. In May and June of that year, Mugabe’s lieutenants orchestrated a campaign of beatings, torture and murder against Tsvangirai’s workers and supporters. Tsvangirai, who won more votes than Mugabe in the first round, quit the race days before the runoff.

A senior ZANU-PF leader offered a blunt assessment of his party’s current political quandary, acknowledging Tsvangirai as a formidable opponent.

"Morgan has been in the making for 10 years," he said, using Tsvangirai’s first name. "He has contested three elections. So there’s fear he has momentum. Who among our so-called leaders can face Morgan if the old man is gone?"

© 2011 The New York Times Company