Mary Kay Lanthier


Nominated for the United States District Court for the District of Vermont on May 23, 2024.

  • Court District Court
  • Date Nominated

On May 23, 2024, President Biden nominated Mary Kay Lanthier to the United States District Court for the District of Vermont. Lanthier currently serves as a supervising attorney at the Rutland County Public Defender’s Office. Through her extensive experience as a public defender, Lanthier will provide the bench with much-needed professional diversity, if confirmed.


Mary Kay Lanthier was born in 1971 in Rutland, Vermont. She received her B.A from Amherst College in 1993 and her J.D. from Northwestern University School of Law in 1996.

Legal Experience

Lanthier began her legal career as a trial court law clerk for the Chittenden County District Court. During her first year as a law clerk, Lanthier was assigned to a criminal trial court in Chittenden County, where she gained invaluable experience observing judges in the state’s busiest criminal court. She drafted decisions for motions involving Fourth, Fifth, and Sixth Amendment issues and witnessed numerous evidentiary hearings and jury trials. Lanthier also assisted judges by drafting jury instructions and ruling on motions in limine. In her second year, Lanthier’s responsibilities expanded to include civil, family, and criminal dockets in Addison County. She primarily supported the judge in civil court, drafting decisions in cases involving breach of contract, the exclusive remedy provisions of workers’ compensation, foreclosures, and jurisdictional issues. Additionally, she assisted during civil jury trials, further honing her legal skills.

After completing her clerkship, Lanthier joined Keiner & Dumont, P.C. in Middlebury, Vermont in 1998. As an associate at this small law firm, she focused on family law, workers’ compensation, and criminal cases. Her duties included legal research and writing, drafting pleadings, and participating in litigation activities such as depositions, court hearings, and mediations. She also provided crucial litigation support in civil cases, including document review and appellate filings. In 2000, Lanthier transitioned to the Addison County Public Defender’s Office, where she represented low-income individuals charged with felonies and misdemeanors. Her role involved leading in arraignments, discovery, depositions, motion hearings, criminal jury trials, and sentencing hearings, demonstrating her dedication to public defense.

In 2003, Lanthier returned to private practice at Marsh & Wagner, a small law firm in Middlebury, Vermont. There, she continued to practice family law, real estate law, and criminal defense. Her responsibilities included drafting discovery, conducting depositions, and leading in contested court hearings, including criminal jury trials, solidifying her diverse legal expertise and commitment to her clients. In 2007, Lanthier returned to public service by joining the Rutland County Public Defender’s Office. Several months after joining the office, she was promoted to supervising attorney. In this role, she represents individuals charged with various crimes who have been determined by the court to be financially unable to afford counsel, advocating for clients at all stages of the trial court process. In addition to her representation and litigation duties, Lanthier oversees the attorneys, investigators, and support staff in the office, ensuring the smooth daily operations and professional development of the team. She manages individual caseloads, providing guidance and support to her colleagues. Lanthier also collaborates with the court and other agencies involved in the judicial process, working to develop and implement efficient and effective policies and procedures. Her leadership and dedication to justice make her an invaluable asset to the public defender’s office and her clients.

The following cases are representative of Lanthier’s legal career:

State v. Cameron

State v. Cameron, No. 1700-11-07 Rdcr (Vermont Superior Court, Rutland Criminal Division) (Zonay, J.)

Ms. Cameron served as a guardian ad litem for a child involved in a highly contentious divorce proceeding. On November 16, 2007, she faced charges of being an accessory after the fact for allegedly helping to hide the mother and child after the child accused the father of abusive behavior. The mother was charged with custodial interference. Lanthier played a crucial role in this case. She conducted thorough pre-trial discovery, including taking depositions from both the child and the allegedly abusive father. The state sought to restrict Cameron’s ability to present a lawful defense, which argued that she acted in good faith to protect the child from real and imminent physical danger. Demonstrating her legal acumen and commitment to justice, Lanthier fought to ensure this defense was considered. Ultimately, the state dismissed the charge moments before jury selection.

State v. Goodwin

State v. Goodwin, No. 517-3-13 Rdcr (Vermont Superior Court, Rutland Criminal Division (Dimauro, J.)

On March 25, 2013, Mr. Goodwin faced charges of burglary and grand larceny, accused of entering a home without permission and stealing cash from a safe. Throughout two police interviews, Goodwin adamantly denied any involvement. However, during a third interview, a police officer presented him with a fabricated laboratory report, complete with the official logo of the Vermont Forensic Laboratory, falsely claiming that Goodwin’s fingerprints were found on the safe. Confronted with this fake evidence, Goodwin confessed to the crime. Lanthier played a pivotal role in defending Goodwin. She filed a motion to suppress his statements, arguing that the use of the fabricated laboratory report rendered his confession involuntary and violated his rights under the United States and Vermont Constitutions. The court agreed, ruling that under the circumstances, the confession was indeed involuntary and suppressed Goodwin’s statement. Thanks to Lanthier’s diligent and strategic defense, the state dismissed the charges against Goodwin, highlighting her commitment to protecting her client’s constitutional rights and her effectiveness as a defense attorney.

State v. Cunningham

State v. Cunningham, Nos. 222-5-05 Ancr, 223-5-05 Ancr (Vermont Superior Court, Addison Criminal Division) (Katz, J.), rev ‘d, 2008 VT 43, 183 Vt. 401 (2008)

On May 19, 2005, Mr. Cunningham was arraigned on possession of cocaine charges stemming from two separate motor vehicle stops within days of each other. The first stop occurred because a registration check revealed that the vehicle’s registered owner had a suspended license. Based on uncorroborated information suggesting Cunningham’s involvement with drugs, the police extended the stop to conduct a canine sniff. The dog alerted, leading to a search warrant and the discovery of cocaine in the vehicle. A few days later, Cunningham was stopped again for a faulty brake light. The officer, aware of the previous stop’s outcome, conducted another canine sniff, which also resulted in the dog alerting and a subsequent search warrant that uncovered more cocaine. Lanthier played a pivotal role in defending Cunningham. She filed motions to suppress the evidence in both cases, arguing that the police had violated Cunningham’s rights under both the United States and Vermont Constitutions by impermissibly extending the motor vehicle stops without reasonable and articulable suspicion. Although the trial court denied these motions, Lanthier preserved Cunningham’s right to appeal by entering conditional guilty pleas and filing a notice of appeal.

The appellate division of the Office of the Defender General took over the case, and the Vermont Supreme Court ultimately ruled in favor of Cunningham. The court concluded that the police officers had violated the Vermont Constitution by unjustifiably extending the motor vehicle stops in time and scope. This victory was a direct result of Lanthier’s diligent and strategic defense efforts.


Professional Activities and Accolades

Outside of her work in the office, Lanthier actively contributes to the legal community through her involvement in several key committees. She is a member of the Criminal Panel of the Committee on Model Jury Instructions, where she collaborates with members from the judiciary and the prosecutor’s office to review and update model jury instructions for statewide use. Her role involves conducting legal research, reviewing draft instructions, and suggesting modifications for the committee’s consideration. She participates in regular meetings throughout the year to ensure the instructions remain current and effective. Lanthier also serves on the Advisory Committee on the Rules of Criminal Procedure. This committee is responsible for reviewing and recommending modifications to Vermont’s Rules of Criminal Procedure. In this capacity, she works with other members to review court rules, propose revisions, and respond to feedback requests from the Vermont Supreme Court. Her contributions are vital in maintaining the integrity and functionality of the state’s criminal procedures. Since her induction in 2018, Lanthier has been an active member of the Vermont State Committee of the American College of Trial Lawyers. She chaired the committee from 2021 to 2023. This prestigious committee identifies outstanding trial lawyers in Vermont who exhibit the highest standards of ethical conduct and civility. Lanthier’s work helps uphold the college’s mission to maintain and improve the standards of trial practice, professionalism, ethics, and the administration of justice.

Lanthier has been appointed by the chair of the Vermont Professional Responsibility Board to lead one of several hearing panels. These panels are responsible for hearing allegations of attorney misconduct, determining if misconduct has occurred, and deciding on appropriate sanctions. In addition to this role, Lanthier actively contributes to the professional development of young lawyers through the Vermont Bar Association. She presents at full-day trial academies, teaching trial techniques to both civil and criminal litigators. Her dedication to education extends to the Vermont Police Academy, where she participates in mock trials, demonstrating and explaining the court and trial process to cadets. Lanthier also volunteers as a judge for the regional round of the National Trial Competition, sponsored by the Texas Young Lawyers Association, showcasing her commitment to fostering the next generation of trial lawyers. Furthermore, she engages with the community by visiting classrooms to educate students about the court process, inspiring and informing future legal minds.