im 100% canadian, I dont live in the US and wondering about your system.
so as i understand your political system, a president can only hold office 2 terms. in Trumps case, he served once already, does that mean he can only serve one more, or is the clock reset and he gets a shot at 8 years?
Not always voluntary. Some tried for a third term and failed. Theo Roosevelt tried for a third term in 1912. Though his first term was taking over after McKinley was assassinated, but it was only some months in, and that would be covered as a first full term under the later amendment.