This is seen as the latest sign that she may be destined for high office.
In a country where the path to power is paved with academic letters, analysts said the timing of the first lady’s surprise qualification was no coincidence.
Armed with a PhD, a seat in the ZANU-PF politburo and her 90-year-old husband’s ear at home, Grace has become a political force as the battle hots up to succeed the only leader Zimbabwe has known since independence in 1980.
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Some have even speculated that Africa’s oldest leader is grooming his 49-year-old wife, nicknamed “Gucci Grace” for her reputed dedication to shopping, to take over.
Although her ZANU-PF credentials are thin, a group of female members recently launched plans to install her at the helm of their Women’s League. Tongues wagged harder still when she completed her doctorate last week, just three months after it was announced that she was doing one.
“This is a political conferment. A lot of politically connected individuals have been getting free degrees here and at other state universities,” a source at the University of Zimbabwe (UZ), whose chancellor Robert Mugabe has seven degrees, told The Zimbabwean, an opposition newspaper.
The UZ declined to comment but a source there told Reuters she enrolled for a masters in 2011 and her tutor considered her research to be “ground-breaking and contributing enormously to the body of knowledge” so it was upgraded to a doctorate.
Her qualification was celebrated in ZANU-PF, where it was also taken as a sign of her rising prominence.
“It was not given. It was acquired quietly without her telling the world,” ZANU-PF Member of Parliament Justice Mayor Wadyajena said a day after her graduation.
“Women, youths and chiefs say to Dr. Mugabe, the sky is the limit.”
One ZANU-PF politburo member told Reuters that Mugabe, who has always kept rivals guessing on his next move, could step down once he has secured a final five-year term in 2018 – by which time he will be 94 – to make way for his wife.
However, this could prove too much for ZANU-PF generals who have always stated they will not recognise a leader who did not fight in the 1970s liberation war against the white-minority government of then-Rhodesia.
That includes Grace, a secretary in the presidential office when she met Mugabe and started an affair while his first wife, Sally, was terminally ill.
“Being the Machiavellian political operator he is, Mugabe is wise enough to know the red line in ZANU-PF which he himself cannot cross,” said Eldred Masunungure, a political science lecturer at the University of Zimbabwe.
“So I clearly dismiss the possibility of her taking over the crown. The crown is too heavy. She will be swallowed whole. ZANU-PF is more and more carnivorous and she will be consumed.”
If reports in Mugabe-controlled state media are taken at face value, Grace’s support inside and outside the party is sky high, with senior officials affirming fawning support for the “queen” and openly stating she is free to seek higher office.
Barring any last minute glitches, she will be appointed head of the party’s Women's League in December.
State media also portray her as a ZANU-PF unifier amid the open tussle between vice president Joice Mujuru and justice minister Emmerson Mnangagwa to slide into Mugabe’s shoes.
If the president dies in office or retires mid-term, the constitution says the ruling party is responsible for electing a successor.
But on closer inspection, Grace’s internal position diminishes, particularly since her Women’s League ascent ruffled feathers by bending rules requiring candidates to serve for 15 years as a senior official first – rules she failed to meet.
Furthermore, without the eventual protective presence of her husband, analysts say her influence shrinks further, more likely leaving her at best a broker in the succession struggle rather than an outright contender.
Grace herself alluded to such internal opposition in a speech at her orphanage in Harare last month.
“There are people who want to drag me on the tarmac when the President goes,” she said.
Outsiders are concerned that the rise of Grace, who portrays herself primarily as mother, businesswoman and philanthropist, throws more confusion into the already messy dynamics of a post-Mugabe Zimbabwe.
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This is the last thing the country needs as Harare – ostracised by the West for the last decade because of allegations of rights abuse and vote-rigging by Mugabe – tries to court foreign investment and normalise ties with the IMF and other organisations to revive a moribund economy, analysts say.
“Mugabe may well be using his wife to extend his options but it’s fundamentally irresponsible,” said Piers Pigou, the International Crisis Group’s southern Africa representative.
“Instead of trying to develop some clarity on where things are going, we have this hyped up side show where everybody and their auntie is trying to work out what this means.”