Assuming the U.S. President is convicted of a crime in their unofficial person, what happens next?

Question

Assuming that, e.g., a sitting President went and shot somebody, and was duly convicted by a jury of his/her peers, etc., in...let's say Washington D.C.... What would happen to the sentence? Would the President continue to be the President in jail? (Admittedly, this leaves out the whole "wouldn't they have been impeached before this" question...but let's assume that Congress is doing something weird again.)

To reiterate: This question does not ask if a sitting President can be convicted of a crime. This question asks what happens to the sentence if and when a sitting President is convicted of a crime, which appears to be possible according to Can the US president be charged of crime such as murder while in office?

Answer 1

To start, for this hypothetical to happen, a whole bunch of decisions contrary to sanity have to happen:

1. The Vice President and President Pro Tempore do not invoke the 25th Amendment to temporarily remove the President from office
2. Congress does not issue Articles of Impeachment
3. The President does not pardon himself
4. The District Attorney decides to prosecute the sitting President rather than waiting for his term to be over

There are probably more I'm missing. With that out of the way, in theory there's no law that says a President cannot serve while in prison, and simply being a felon does not disqualify him from the Presidency. The judge might order that while he was still serving as President, he serve his time under house arrest - he'd constantly be surrounded by police officers, so it would be pretty difficult for him to run, and it would keep him as as able as possible to keep performing the official functions of the office. The judge could also just defer his sentence. Putting him in regular prison would have serious national security implications, both in terms of protecting his person and in allowing him to effectively serve as Commander-in-Chief, so the government could probably make a compelling case against putting a sitting President in prison.

According to this Senate Report, the President will also continue to receive Secret Service protection once he leaves office, so long as he is not removed by Impeachment. There doesn't seem to be a provision against that protection if the President is in prison, so the Secret Service would be obliged to find a way to protect him while he is in prison. Most likely this would mean he would be put in an isolated prison wing, possibly with Secret Service protecting his section.

Answer 2

The President would first be impeached by the House and, if upheld by the Senate, would be removed from office. The Vice President would become President, and the impeached President would become a common citizen again. Following that, the former President would be given an actual criminal trial and convicted. He would in theory not be tried before the trial (this was a major source of trouble prior to the Clinton Impeachment).

In theory, the President has Sovereign immunity, so while he is President, he cannot be charged with a crime. Impeachment, while it's supposed to be granted for "High Crimes and Misdemeanors" has historically occurred for "any reason that gets Congress mad enough to demand your removal from office". The Supreme Court has also said that Impeachment is entirely political and thus not up for review by the Judicial branch of government (also, Impeaching a Federal Judge is more common then an executive officer. 15 of the 19 people impeached by U.S. Congress held a Judicial office (Two Presidents, one Cabinet Member and One Senator were impeached. In fact, the Judiciary is the only branch that has lost office holders as a direct result of Impeachment found Guilty by the Senate).

While never impeached, Nixon resigned before his articles of Impeachment were voted on the House Floor. Upon his resignation, Nixon was given a Presidential Pardon by President Gerald Ford, an act which was very unpopular at the time, but is today viewed by some as an act of healing the nation (keep in mind, Nixon won all but Massachusetts in the last election so his ousting was deeply hurtful to the nation. A trial against Nixon would have only made the wounds deeper.).