Mr. Mnangagwa, who was backed by the military, including the top military commander, Gen. Constantino Chiwenga, said he had been “in constant contact with the service chiefs throughout” the recent events.
Mr. Mugabe, who was himself last seen in public on Sunday, tendered his resignation in a letter to Parliament on Monday, just after lawmakers had begun impeachment proceedings. The military, which has held him under house arrest, released no details Wednesday about Mr. Mugabe or his family.
In an effort to win legitimacy for the new government, Mr. Mnangagwa’s allies have taken great pains to paint his elevation as following the rule of law. Under their direction, ZANU-PF expelled Mr. Mugabe and named Mr. Mnangagwa as its new leader. Then it moved to impeach Mr. Mugabe.
The Constitution allows the governing party to nominate an individual to the presidency if the office is vacant.
The trouble, legal experts and human rights group say, is that Mr. Mnangawa’s allies have influenced real-world events. In addition to placing Mr. Mugabe under house arrest, the military, which does not have the authority to arrest individuals, has detained Mr. Mnangagwa’s political rivals, whose whereabouts remain unknown.
“That’s what ZANU-PF has always done,” said Rashid Mahiya, the executive director of HealZimbabwe Trust, a human rights group. “It’s not your usual dictatorship. There’s a veneer of legality and constitutionality in all they do, but the politics take place behind the scenes.”
Some have also raised questions about the constitutionality of Mr. Mnangagwa’s nomination. Before he was fired, he was one of Mr. Mugabe’s two vice presidents. The other, Phelekezela Mphoko, belonged to the rival faction, led by Mr. Mugabe’s wife, Grace Mugabe.
According to the Constitution, in the event of a vacancy, one of the vice presidents automatically becomes president while the governing party has 90 days to nominate an interim president. Mr. Mphoko, as the only vice president, appeared to be in line to become president upon Mr. Mugabe’s resignation.
On Sunday, Mr. Mnangagwa’s allies in ZANU-PF expelled Mr. Mphoko from the party. Even so, he could have been dismissed as vice president only by the president himself, said Greg Linington, an expert on constitutional law at the University of Zimbabwe.
But Mr. Mphoko, who was visiting Japan when the military took over, has not returned to Zimbabwe, fearing for his safety.
“No one even knows where exactly he is,” Mr. Linington said. “So the practicalities of the situation are that he’s not available to perform the functions of the office.”
On Tuesday, minutes after Mr. Mugabe’s resignation was announced, thousands of Zimbabweans flooded Africa Unity Square in Harare in an outpouring of celebration. The mood was captured Wednesday morning in some of the nation’s privately owned newspapers, including Newsday, whose cover showed Mr. Mugabe walking away under the headline, “Adios Bob!”
But for ZANU-PF coming to grips with Mr. Mugabe’s legacy was more complicated. Like all other liberation parties in southern Africa, including Nelson Mandela’s African National Congress, ZANU-PF has justified its uninterrupted hold on power since independence in 1980 by harking back to its role in liberating black Africans from Europeans.
On Wednesday morning, a day after moving to impeach Mr. Mugabe, there were indications that ZANU-PF was re-embracing its former leader, or at least some elements of the Mugabe legacy.
“ZANU-PF pays tribute to Mugabe,” read the banner headline on the front page of the state newspaper, The Herald, which, since its founding in 1891 has helped create and propagate the myths of those holding power — from British colonizers to white settlers to ZANU-PF under Mr. Mugabe and now Mr. Mnangagwa.
In its lead editorial, The Herald said, “Fare thee well, Cde President,” using the term Comrade.
“It must be pointed out from the outset that Cde Robert Gabriel Mugabe’s legacy, though it was being chipped at in the end, was not being tainted by his own hand but much like Adam and Samson before him, the blame falls on his partner,” the editorial said, referring to Mrs. Mugabe.
Some ZANU-PF veterans have compared Mr. Mugabe to Mao Zedong — both of whom were married to young, ambitious wives in the twilight of their careers.
Like Mao, Mr. Mugabe occupies such a dominant role in his party’s liberation mythology that ZANU-PF would find it difficult to deny his legacy.
“ZANU-PF can never portray Mugabe in a bad way,” said Agrippah Mutambara, a hero of the liberation war who later served as Mr. Mugabe’s ambassador to three nations. “What is going to happen is that all the blame will be leveled at the wife.”