States with DA "filing charges" as a gatekeeping mechanism

Hey everyone--

I am currently working on a "'airing of grievances" -type project for the state I practice in. I am a private attorney who also takes appointed cases. My state has few, if any, procedural legal protections in place for criminal cases and I worry that everyone here has just grown to accept it as fact, rather than doing something about it at the procedural level. I thought I would ask yall about experience and procedures in your respective states, so I can compare it with my own.

Though there are many problems we have, I thought i'd start at the very beginning: I hear about other states having a process where the DA decides whether or not to file charges. This is a bizarre concept to me in my state. Here in South Carolina, the police issue an arrest warrant, signed by a magistrate judge (who is not required to be a lawyer btw), then the person is arrested and has a bond hearing soon afterwards. After that, the warrant is transmitted to the Prosecutor's office (our "Solicitor's Office" is the same thing as a "district attorney's office", we just like to be different. The Solicitor's office then has the case, they do not need to do anything else (except indict the case eventually, but that will likely be a separate discussion).

My question is-- in other states, is there a decision made by a prosecuting attorney about whether or not to prosecute the case? If so, does this happen before the warrant is issued? Before/after the arrest is made? If the decision is made not to file charges, is it solely based on strength of the evidence, or is there sometimes an agreement made with defendant or defense attorney ("your guy has no record, we'll dismiss it with leave to re-open and your client better not get in trouble for six months"- something like that).

Depending on responses to this post, I will probably ask additional questions about your state(s) in the future, but I decided to start with the beginning of the case and go from there. So, if you don't mind, please let me know how the process works in your state, which state you're in, and if there's any statutory/Rule of Crim Procedure authority that guides that process in your state so I can point to something In writing when/if I present my project to our legislature.