Drug Possession

Drug Possession Attorney in St. Louis

Defense from a Former St. Louis County Prosecutor

When you’re charged with drug possession, knowing how the other side builds its case can make a real difference in how your defense is built. Attorney Jack Cavanagh spent years as an Assistant Prosecuting Attorney for St. Louis County before founding Cavanagh & Associates in 1962. That background shapes how he approaches every possession case: he knows how prosecutors evaluate evidence, decide whether to charge, and prepare for trial.

You’ll work directly with Attorney Cavanagh throughout your case, not a paralegal or a junior associate. Over 50 years of Missouri trial experience means he’s handled the full range of what possession charges can look like, from first-time arrests to cases complicated by prior convictions.

A drug possession charge in St. Louis moves fast. Call Cavanagh & Associates at (314) 309-2799 to schedule a free consultation with Attorney Cavanagh and talk through where your case stands.

What a Drug Possession Charge Looks Like in Missouri

Missouri classifies controlled substances into five schedules based on their potential for abuse and accepted medical use. Where a substance falls on that schedule, and how much of it was allegedly in your possession, drives how a charge gets filed and what penalties you’re looking at.

Under RSMo 579.015, possessing any controlled substance other than 35 grams or less of marijuana is a class D felony, carrying up to seven years in prison and a fine of up to $10,000. A prior conviction for a controlled substance offense can elevate what would otherwise be a straightforward possession charge. That kind of prior and persistent offender enhancement is one reason the charge you’re facing now deserves serious attention, even if the amount involved was small.

Marijuana Possession Penalties

Missouri’s marijuana possession penalties depend on weight and prior history:

10 grams or less: Class D misdemeanor, fine up to $500 (but a prior offense can elevate this to a class A misdemeanor)
More than 10 grams, up to 35 grams: Class A misdemeanor, up to one year in jail and a fine up to $2,000

Missouri’s Constitutional Amendment 3, approved in 2022, created an adult-use exception: adults 21 and older may legally possess up to three ounces of marijuana without criminal or civil penalty. These penalty tiers apply when possession exceeds that limit or when someone doesn’t qualify under the amendment.

Why St. Louis Clients Choose Cavanagh & Associates

Attorney Cavanagh’s former-prosecutor background doesn’t just add credibility. It means he comes to your defense already knowing how possession cases are evaluated on the other side of the table. He knows what evidence prosecutors rely on, where cases tend to be weak, and what arguments carry weight in plea negotiations.

Clients receive a tailored defense strategy based on the specific facts of their case. Cavanagh & Associates combines aggressive trial preparation with the personal attention that keeps you informed at every step. Martindale-Hubbell has recognized Attorney Cavanagh with a Distinguished rating in 2018, 2019, and 2022, reflecting a long record of professional conduct and client service.

Schedule a Free Consultation

Cavanagh & Associates offers free consultations for drug possession cases. You’ll speak with Attorney Cavanagh directly about the facts of your situation and what options may be available to you.

Call Cavanagh & Associates at (314) 309-2799 to schedule your free consultation.

Where Your Case Is Heard in St. Louis

Which court handles your possession case depends on where the arrest occurred. Drug possession charges arising within the City of St. Louis are prosecuted in the 22nd Judicial Circuit Court. Charges arising in St. Louis County communities, including Affton, Florissant, Kirkwood, and Oakville, fall under the 21st Judicial Circuit Court.

Both courts operate treatment and drug court programs that offer supervised substance-abuse treatment as an alternative to traditional sentencing for eligible nonviolent offenders. Drug treatment court is worth exploring when it fits the circumstances, and Attorney Cavanagh can assess whether it’s a realistic option in your case.

Common Defenses in Missouri Possession Cases

Missouri drug possession cases often turn on the same core legal questions. Three come up frequently:

Unlawful Search & Seizure
Evidence gathered without a valid warrant or sufficient probable cause may be suppressible under the Fourth Amendment. When law enforcement exceeds its authority during a stop or search, the evidence obtained may not be usable at trial.

Constructive Possession
Actual possession, meaning the substance was on your person, isn’t the only theory prosecutors use. Constructive possession requires the state to prove you knew about the controlled substance and had control over it. This becomes a real issue when drugs are found in a shared vehicle or a home with multiple occupants.

Lack of Knowledge
Sometimes called unwitting possession, this defense applies when the defendant genuinely didn’t know a controlled substance was present. If someone else placed the substance in your bag, car, or home without your awareness, that’s a viable argument worth examining.

Collateral Consequences of a Drug Conviction

The sentence imposed by the court is only part of what a drug possession conviction costs. A conviction becomes part of your permanent criminal record, and that record follows you. A felony drug conviction can limit employment opportunities when background checks are involved, affect housing eligibility since many landlords screen for criminal history, and restrict your right to own or possess a firearm under both Missouri and federal law.

These consequences don’t expire when a sentence does. If you’re facing a possession charge in St. Louis, talk to our drug possession lawyers before the case moves forward.

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Read Stories Directly From People We've Helped

"Jack did a great job representing me"
Jack did a great job representing me while dealing with a high conflict ex. He was able to tell me what to expect and what was worth fighting for and did it in a way that made it easy to accept.

- Dustin G.
"I would recommend Mr. Cavanagh as well as use him again in the future."
Mr. Cavanagh was very patient in dealing with all of the difficulties of my case. He was pleasant to work with to get the child support and custody worked out in a way that was fair. He showed real concern for the welfare of my son. He was professional in guiding me with regards to counseling and getting my sons voice heard throughout the case as well. Lastly he was thorough in that he went through the original divorce decree and made sure I received what I should have gotten during the divorce. I would recommend Mr. Cavanagh as well as use him again in the future.

- Former Client
"I highly recommend him"
Jack took over my divorce case and made a seemingly endless divorce process (nearly 4 years with mediation, continuances and a former atty.) come to a quick and agreeable settlement. Jack is an effective and seasoned attorney that made easy work of the negotiations. He is respectful and concerned for his clients. His associates were friendly and helpful, ensuring that all paperwork was completed in a timely and accurate fashion. I highly recommend him if you are going through a difficult divorce.

- Carol
"I was beyond satisfy"
Mr. Jack Cavanagh was my attorney getting me removed from an child birth certificate that wasn’t my child. He made the process very easy and timely manner the communication was very good and I was beyond satisfy with the outcome and service Thank you Mr.Jack and Ms.English

- Demetric L.
"Two things define you. Your patience when you have nothing, and your attitude when you have everything."
My experience with Mr. Cavanagh was very pleasant. I was kept informed about what was going on with my case. Phone calls were returned promptly and everything was explained to me. Knowledgeable, personable and fair - can't ask for much more than that. He was on my side. One more thing.... he's not a pushover when it comes to the opponent! Love it!

- Terri Buckner
"Attorney Cavanagh is a fantastic lawyer"
Attorney Cavanagh is a fantastic lawyer. His experience is unparalleled. He does an excellent job of keeping his clients informed, and he is an outstanding advocate in court. He is kind and patient, and genuinely cares about his clients. I am proud to know him, and grateful for his help!

- Rick V.
"Would recommend"
Jack resolved a case from 1500 miles away in a timely manner. Professional throughout the entire process, took the time to understand my needs as a client and fulfilled them without ever wavering in his commitment or price. Would recommend.

- Patrick S.
"Great Team! Highly Recommended."
I worked with Jack and Eka recently and must say they exceeded my expectations. Great communication and compassion for what you’re dealing with. I wouldn’t hesitate to go back to them for any of my legal matters.

- Donald Salisbury

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