You seem to have failed to see the thorniness of the problem maybe because in the current instance (Le Pen's ban by the French judiciary) you agree with the outcome.
Probably impossible to separate Le Pen's disqualification from the situation in the U.S. It's the song of the day. I seem to recall some account arguing in 2020, nominally on their expertise as a lawyer, that the election result could not be determined except in the courtroom. If you asked in 2020, should lawyers be disgraced if not disbarred for attempting to nullify the election - answer from GOP would be no. When asked today, suddenly answer is yes.
I agree only in the sense that K think that politicians should be punished for their wrongs.
I would only see thorniness is the courts refused to punish Le Pen out of fear of punishing a somewhat popular politician, as this would embolden others to act in ways to break the rules, and would undermine the independence of the court, which is a core tenet of a functioning democracy.
I think you only see thorniness here because you wanted Le Pen to keep doing her thing. See? it works both ways.
What you are describing is the judiciary in any functioning democracy. Separation of powers requires an independent judiciary system.
They have to be unelected, so they keep their independence when evaluating if the laws are being applied according to the written law.
> Now that's okay to a degree, but the question is: where does the buck stop?
With proper separation of powers and an independent justice system, like the one that judged Le Pen and found her guilty.