The question of what would happen if someone is elected president of the United States while serving time behind bars is a valid one, but one without a clear-cut answer.
Nothing may preclude someone from serving as president from prison. The U.S. Constitution doesn’t address this circumstance, and it would likely be determined by federal courts.
The U.S. Constitution only states a candidate for president must be "a natural-born citizen," "at least 35 years old," and “a resident of the United States for at least 14 years."
UCLA law professor Richard L. Hasen explained, "It does not bar anyone indicted, or convicted, or even serving jail time, from running as president and winning the presidency."
The men who drafted the Constitution didn’t plan for this issue. However, there are two Constitutional Amendments that may bar someone from serving as president while incarcerated.
The 14th Amendment disallows anyone from serving as president if they "have engaged in insurrection or rebellion against the same, or given aid or comfort to the enemies thereof."