List of Presidents of the United Planets/Reboot
From Legion Wiki
The political system by which Presidents were chosen is not entirely clear - Chu and "McCauley" were both elected as EarthGov presidents and by extension United Planets presidents. However, after Chu's impeachment, Brande was drafted without an election, and never faced an electorate before being impeached himself over the Blight crisis. Following this, it is not clear whether Vice-President Wazzo became the president until the forthcoming election, or whether "McCauley" was immediately drafted. Either way, he would win at a landslide in the following election. After he was discovered to be an imposter, VP Wazzo then became president.
[Any dates given in post-Zero Hour comics "slide" so that the current date was, with a couple of mistakes excepted, always the "present day+1000 years" and are thus apocryphal.]