> Consider, for example, the various congressional investigations of Hilary Clinton in 2014/2015. If everybody was guilty of some crime(s) punishable by jail time, it would follow that some of those overly brought criminal statues would have come up in those proceedings, considering there were any number of high-powered lawyers tasked with finding anything against her that would stick.
There are a lot of reasons to expect it not to be easy in that specific case.
The first is that she's a career politician and a lawyer married to a lawyer. That removes most of the low hanging fruit. She would be more aware of more of the laws that are easy to avoid breaking if you know they exist but most people break all the time only because they don't. Then she's not going to let herself be questioned without consulting legal counsel, which makes it a lot less likely they can prove something by getting her to admit to it.
On top of that, there are two kinds of laws that people break all the time, and neither of them are really suited for political cases like this.
The first is the really obscure laws or unusual circumstances. You have a pocket knife, you walk under an overpass which is technically state owned property, there is a law in that state prohibiting possession of a weapon on state property, etc. Or you have an unusual fruit in your bag on when you cross a border. Everybody breaks laws like this unintentionally, but these are the ones where (absent a surveillance state) it's a lot easier to choose an overpass and find a person walking under it than to choose a person and try to find evidence of a violation like this, and charging a prominent politician with something like that would immediately lead to mockery and claims of a politically-motivated prosecution.
The other is the ultra-broad laws they can charge anybody with (e.g. CFAA) because technically everyone violates them regularly. The problem there isn't finding violations, it's that the prosecutors won't want to risk using those laws in cases like that, because they find them too valuable in general and it's prominent cases like that which lead to them being narrowed by judges. The power of those laws for prosecutors is that you might be able to beat the charge, but only by spending millions on lawyers, which causes ordinary people to plead guilty. That doesn't work against someone like Hillary Clinton because she'll spend the millions on lawyers -- and potentially cost prosecutors future use of that law against the proles.
> The Clinton example may be imperfect because of partisanship, but I can't currently think of any other widely-known case where prosecutors were trying to "throw the book" at someone.
Think of cases where the accused isn't rich or politically connected, e.g.:
https://en.wikipedia.org/wiki/United_States_v._Manning
In particular, look at all the ancillary charges they tack on to make sure something sticks and consume defense resources. That's really common and is typically even worse in less high profile cases where there is less scrutiny of their absurdity.