Military Expert Advisor

Gary S. Barthel, Lieutenant Colonel, U.S. Marine Corps (Ret)

Military Law Expert Witness & Consultant

Gary S. Barthel

Expert Witness and Consultant

Gary S. Barthel is a nationally recognized expert in military justice, court martial offenses and procedures, and military administrative actions. A retired Marine Corps Lieutenant Colonel and former Judge Advocate, he brings nearly 40 years of combined military and civilian legal experience to his work as an expert witness, consultant, and media analyst.

Civilian Legal Experience

Since retiring from active duty in 2003, Gary has represented servicemembers from all branches in both military and civilian courts. His civilian litigation and appellate work strengthen his ability to interpret and explain how military decisions, regulations, and evidence affect civil or criminal outcomes.

His expertise is frequently used to:

Analyze complex discovery
Identify military-specific evidence
Explain military policies and procedures
Translate military records for civilian courts
Evaluate damages and administrative impacts
Bridge military and civilian legal systems

Expert Witness & Consulting Work

Gary now focuses on serving as a military law expert witness and consultant for law firms, investigative teams, and government or media organizations.

He provides:

Case evaluation and analysis
Assistance with obtaining military discovery
Written expert opinions
Testimony
Military records interpretation
Regulatory and policy clarification

Military Background

Gary served 20 years on active duty in the U.S. Marine Corps, holding key roles across the military legal system:

Prosecutor and Defense Counsel in courts-martial
Advisor for criminal investigations and misconduct cases
Counsel for administrative hearings, separation boards, and disability evaluations
Staff Judge Advocate (General Counsel) to multiple Commanding Generals and Commanding Officers
Legal advisor on civil claims, government ethics, and the use of federal resources
Manager and trainer of large legal teams (20+ attorneys, 40 staff)

His military work required deep mastery of regulations governing discovery, promotions, performance evaluations, disability ratings, and military pay and benefits.

Education & Credentials

LL.M., Military Law — U.S. Army Judge Advocate General’s Legal Center & School (University of Virginia)
Specialized training across all major areas of military law for every branch of service
Former Federal Prosecutor, U.S. Attorney’s Office (Alexandria, VA)
Assignments with the U.S. Department of State at embassies in Tanzania and Greece
Secret service support for senior U.S. officials, including the Secretary of State and the U.S. Ambassador to the United Nations

“Watching Barthel in Court is tantamount to attending a masters class in trial advocacy.”

CBC News | Hanomansing Tonight: Sending military to L.A. a ‘gross overstep’ by Trump administration

Stolen Valour: Gary Barthel on iCrime with Elizabeth Vargas

Media & Public Commentary

Known for clarity and objectivity, Gary is frequently sought by journalists, documentary teams, and news networks to explain military justice issues. His ability to translate complex military issues into plain language makes him a trusted source for responsible reporting.

Task & Purpose

Patty Nieberg, Jul 9, 2025

Army lays out policy to search deceased soldiers’ phones for classified info

Gary Barthel, a retired Marine lieutenant colonel and a civilian lawyer who has represented troops in military and civil legal cases said the policy acts as a force protection measure to prevent sensitive military information disclosures.

Snoopes

Megan Loe, June 17, 2025

Unpacking claims that VA doctors can deny care to Democrats, unmarried veterans

“The changes are not likely to have any impact on a nonmarried or Democratic veteran from receiving care and if a care provider refused to provide care because of a veteran’s political affiliation or marital status, they likely would be disciplined for doing so and could lose their license to practice.”

Contact Military Expert, Gary S. Barthel

Gary Barthel provides trusted military expert witness services to legal teams across the U.S., including deposition support, trial testimony, and expert consulting. Based in San Diego, available nationwide.