Former Dictators Leading "Democratic" Insurgencies?

[FEMA Camp Administrator]

I was just reading an article on the 2015 Nigerian presidential election wherein Muhammad Buhari, who I guess was a short-term dictator of Nigeria in the 1980's, was elected democratically as the candidate of the All Progressives' Congress. Recently, Malaysia underwent a similar transfer of power, Mahathir Mohamad, who served as prime minister for over 20 years from 1981 to 2003 being elected in 2018 as an opposition candidate against a former protege(?) of his. The other day I was reading about a different country, whose name escapes me, that was experiencing, or had experienced, a similar election.

So I guess my questions are
1. Is this sort of thing more widespread than these three(?) cases?
2. Is this a generally recognized phenomenon?
3. If so, how do these things tend to work out?
4. Are there any explanations for such?
     a. I would be forced to assume that former presidents, dictators even, have the most legitimacy and the broadest support base from which to launch campaigns against governments they once led. Moreover, they are known quantities.

A few former Soviet republics underwent a superficially similar phenomenon; in both Georgia and Azerbaijan, former Communist party heads (if I'm not mistaken, both with roots in the KGB) were brought back to power via election in the mid-1990's. In Georgia with Shevardnadze, there was an eventual "democratic" transition afterwards. For the Aliyevs in Azerbaijan, no such luck. That said, these men were assuming power in semidemocratic environments and then proceeded to rule as dictators.

EDIT: Upon further research, I may have misremembered the fictional "third case".

[Atlas Has Shrugged]

The communist leader of Benin was eventually returned to power decades later. Same with the Republic of the Congo. I may be mistaken on the exact details of this.

[Dr. MB]

One notable case was that of Getúlio Vargas in Brazil, who led a dictatorship between 1930 and 1945 and later served as democratically elected president in the 1950s.

Daniel Ortega was the communist leader of Nicaragua in the 1980s under the Sandinistas, and was democratically elected president in 2006, but he's definitely trending back in the authoritarian direction.

Nigeria also had another former military leader turned democratic president – Olusegun Obasanjo, who was dictator from 1976 until 1979 and president from 1999 to 2007.

[Edu]

Hugo Banzer in Bolivia, dictator between 1971-1978, elected president in 1997

[H.E. VOLODYMYR ZELENKSYY]

Carlos Ibáñez del Campo, Simeon II/Simeon Saxe-Coburg-Gotha in Bulgaria, IIRC Norodom Sihanouk in Cambodia.

[Dr. MB]

Carlos Ibáñez del Campo, Simeon II/Simeon Saxe-Coburg-Gotha in Bulgaria, IIRC Norodom Sihanouk in Cambodia.

I wouldn't really count Simeon, given that he was 10 years old when he was tsar – but yes, it's an interesting example for sure.

[MASHED POTATOES. VOTE!]

Mahathir Mohamed. Maybe not fitting a strict definition of a "dictator", but definitively had pretty authoritarian record.

Dési Bouterse of Suriname is a former de facto military ruler was later democratically elected.

Olusegun Obasanjo, military leader of Nigeria from 1976 to 1979 became elected President from 1999 t 2007, although first time around he nicely handed over his power to elected government.