If American voters think the stakes are high enough to overlook corruption, isn’t that their prerogative? Voters are the source of truth in a democracy.

No, that's why there's nowhere in any legal code in the US that "running for office makes you immune to criminal charges."

These are two completely distinct systems. By design.

I remember that you are a foreigner (from some corrupt third world county if I recall?) with a limited understanding of American legal history and political culture, but the idea that voters simply get to decide who is a criminal or not is flatly contrary to America's culture.