Denis Sassou-Nguesso (Republic of Congo) — 33 years, nonconsecutive
Age: 73
In power since: It’s complicated. He first was president from 1979 to 1992, when he was defeated in an election. He returned to power in 1997 during a civil war, eventually standing for and winning a presidential election in 2002.
Current election rules: Majority popular vote. Up to three five-year terms, though a 2015 constitutional referendum allowed Sassou-Nguesso to forgo the limits, according to Freedom House, a US nonprofit that promotes democracy. The last election was in March 2016.
