Here’s what hurts you with marijuana, it is illegal to possess, from Mississippi statute:
My understanding of the biology is marijuana, you can’t easily tell based on chemical tests how recently the person used it, so those aren’t even that helpful. But Brasel19 admitted to the arresting officer to having used marijuana shortly before the arrest, which would if this actually was contested at trial be pretty strong evidence against him suggesting he was under the influence of a drug which is unlawful to possess.
So in Mississippi, essentially if they can prove you were under the influence of an illegal substance, it does not matter about field sobriety tests and chemical concentration amounts etc, once they’ve demonstrated you had used it, you’ve met the statutory requirements for a conviction.
Historically, DUI in the past was based on demonstrable impairment. Basically an officer found someone driving drunk, and would testify that say, they found the guy passed out in his car at a stop light. That’s obvious evidence of impairment. Or they asked him to step out of the car, the guy fell out of the car and was unable to stand on his own, and had pissed himself. That’s obvious evidence of impairment. Some people were not so clearly impaired, so they developed a standardized field sobriety test. But “physical signs” of impairment can be successfully fought in court in some circumstances. So they eventually modified DUI laws, in addition to the old way of convicting someone (by collecting evidence demonstrating they were actually impaired) the States introduced “per se limits” of blood alcohol concentration, if you were found to have a BAC above those limits that was a statutory violation. The State did not have to prove you were impaired in any other way, once you were over that limit the law said you were impaired and guilty.
With many states and marijuana, the law is similar to that per se limit, except the limit is “any usage” so if they can prove you were using marijuana and driving, that makes you guilty of impaired driving.
Now, where a lawyer can help the OP is in negotiating this. And btw, Brasel19 you were 100% right to be polite and helpful to the police officer. That can’t always help you, but sometimes it certainly does. And if never hurts you, there is nothing you can do after the incident to repair being an asshole to the cop during the incident. While you made some legal errors, you certainly may have helped yourself by being polite with the police officer.
In some areas of the country, you get your public defender and he’ll talk to the local prosecutor. They may talk to the arresting officer, and they may come to an agreement where maybe the officer doesn’t appear for the court date and the DUI charge is dismissed. But in the last ten years (and I’m not a lawyer or anything) just from my observation localities have gotten less likely to use this traditional “mulligan” technique for letting people out of DUIs. So politically the prosecutor’s hands may be tied.
At the very least though, the fact that there is no minimum jail sentence means your good behavior will insure you will not face jail time for this, and there may be formalized diversion or expungement programs in Mississippi that you can take advantage of.
A lot of states it used to be sort of understood a first offense DUI, unless you had dome something egregious, would get knocked down to reckless driving, but with the more serious approach to drunk driving these days it is not nearly so common anymore.