Yes. Ever since Bill Clinton (and probably before that, I was too young) the President and a non-trivial number of presidential candidates were either under an investigation of some sort, or a threat of such an investigation. Obviously Bill, Hillary, constant threats of investigation of George W Bush and Obama, special counsel investigating Biden, and all the Trump cases. Notably nothing ever comes out of these.

This is ridiculous! It's blatantly political and both parties are guilty of this. The justice system is meant to hold people accountable for breaking the law, not as an additional political mechanism for checks and balances. I haven't looked into the case and don't know the legal precedent SCOTUS used for this decision, but from a consequentialist standpoint this seems to me an obviously good outcome.