Our attorneys specialize in security clearance appeals.  They have dedicated their careers to learning the entire security clearance process from start to finish.  They started by working for the federal government before entering private practice.  Their extensive experience working for the federal government includes over eight years advising clients on revoking and suspending an employee’s security clearance, reporting derogatory information, representing clients in their response to a Statement of Reasons (SOR), and serving in a joint duty assignment for the Defense Office of Hearings and Appeals (DOHA).  Their work at the DOHA allowed them to learn the inner-workings of the Agency responsible for representing the Department of Defense Central Adjudicative Facility (DoD CAF). All of these experiences provide our attorneys a unique advantage over other attorneys and firms who practice in the security clearance niche.


Brett O’Brien

Brett O’Brien’s zealous representation of his clients can only be obtained by having years of experience working for the federal government. Brett knows the system and he knows the government’s strategies. He has been practicing national security law for his entire career. Brett has extensive experience advising the government on temporarily or permanently revoking an employee’s security clearance for different violations of the thirteen adjudicative guidelines.  Therefore, he is able to take this unique experience and apply it to the zealous representation of his clients.

His unique experiences in addition to temporarily working at the DOHA includes: graduating from the Navy’s classified litigation course and the U.S. Army’s Litigation Division’s Federal Litigation course, providing unique knowledge on how to deal with classified reasons for revocation, the U.S. Army’s new prosecutors course; and the U.S. Army’s intermediate trial advocacy course.  In short, the U.S. government provided Brett extensive training on trial advocacy and how to best represent his clients in their security clearance revocations.

Brett worked in and supported the intelligence community for eight years.  He worked for three years supporting the Army’s intelligence units responsible for operations south of the border, which included U.S./Mexico border issues.  He worked for approximately two and half years as the legal advisor for the Army’s counterintelligence organization.  This job included advising the government on counterintelligence investigations as well as assisting technical experts whose focus was on assessing the truthfulness of employees. Throughout these eight years he consistently advised his clients on security clearance revocations.

Brett graduated from Denison University in 2008 and Case Western Reserve University School of Law in 2011.  While at Case Western Reserve University School of Law, Brett co-founded the military law society and was the student responsible for working with faculty on creating a national security concentration within the school.  National security matters are not just a job for Brett, instead national security law has been his career passion. Brett is admitted to practice law in New Jersey, the District of Columbia, New York, and Ohio.

Carl Marrone

Carl Marrone has unparalleled experience as both a prosecutor and a defense attorney in both the military and civilian criminal justice systems.  He brings aggressive confidence to the courtroom, he consistently outworks the opposition, and he relentlessly fights for his clients.  Regardless of the charge, Carl has handled it in the past, and he knows how to get outstanding results for his clients.

Most recently, Carl was a Deputy District Attorney (DDA) for Los Angeles County—the largest local prosecutorial agency in the United States—for just under four years.  He is used to taking on tough cases with very little notice.  As a DDA, he handled every type of criminal case imaginable: from driving under the influence (DUI) to murder.  Carl understands the complexities of domestic violence cases, sexual assault cases, and special victims cases.  He is able to recognize weaknesses in a criminal investigation, and, more importantly, he is able to exploit those weaknesses in the courtroom.

Carl knows how military prosecutors think and act because he used to be one.  He spent about five years on active duty with the United States Army JAG Corps.  He served as a prosecutor at Schofield Barracks, Hawaii, a Special Assistant United States Attorney for the District of Hawaii, and a defense counsel at Fort Knox, Kentucky.  On his very first court-martial as a defense attorney, he secured a full acquittal for a client who was falsely accused of sexual abuse.  In another case, he refused to succumb to a politically-oriented prosecution of a Soldier, who was found not guilty of all but one specification and left the Army without a punitive discharge.  The Army specially trained him at the Sexual Assault Trial Advocacy Course, where he was recognized for his outstanding cross-examination.  He continues to serve our country as a Major in the US Army Reserve JAG Corps.

Carl is a graduate of Claremont McKenna College in 2006.  He earned a Master of Arts (MA) in Criminology and Criminal Justice from the University of Maryland—the #1 ranked program in the United States—in 2008.  He went to law school at Loyola Law School in Los Angeles, which has trained numerous renowned trial advocates.  Carl received the highest grade in his Criminal Law class of about 100 students, he was awarded a scholarship, and he graduated with honors. Carl is admitted to practice law in California and Hawaii.

Alex Carr

Alex is a skilled advocate who leads the Security Threat Assessment practice group at the National Security Law Firm where he focuses on defending clients in Global Entry appeals, Transportation Worker Identification Credential (TWIC) appeals and waivers, Hazardous Materials Endorsement (HME) appeals and waivers, and customs seizures.

The National Security Law Firm is renowned for having one of the largest and most experienced Security Threat Assessment practice groups in the nation. No firm has a stronger record of success in filing claims in these complex areas of law. Moreover, only a handful of attorneys in the United States have any knowledge or experience in these highly specialized areas of law, making Alex an invaluable asset.

Alex works relentlessly to obtain information from the government through requests made under the Freedom of Information Act (“FOIA”) in order to support his clients’ cases. This skill is vital to being able to effectively and successfully represent clients in these areas of law, where the government is notorious for denying and/or revoking credentials without justification or explanation.

Alex also understands that, in order to stay a step ahead of an entity with unlimited resources, persistence and hard work are crucial as the government will often initially deny or redact requests made under the FOIA statute. With Alex’s experience and background, however, he is able to overcome governmental resistance to providing further information.

In recognition of Alex’s abilities as an advocate, clients have described him as “an outstanding attorney-at-law who stands head and shoulders above his peers,” and someone whose “responsiveness, sound judgement, spot-on guidance, insights, and skill demonstrated . . . the marks of an exceptional lawyer – second to none.”

Whether he is drafting an appeal regarding your security threat assessment denial and/or revocation or responding on your behalf to a customs seizure, Alex’s superb written and oral advocacy skills and ability to craft persuasive, novel, and complex legal arguments will maximize your chances of success.

Alex graduated with honors from Ohio University in 2008. He went to law school at Case Western Reserve University School of Law, where he graduated in 2011. Alex is admitted to practice law in Ohio.

Luke Rose

Luke Rose is a native midwesterner that spent nearly 16 years with the Department of the Army serving in various attorney positions throughout the globe.  He served as a National Security Law attorney for the final 12+ years of his career with the Army, advising commanders at all levels on intelligence and security matters.  He advises his clients from the perspective of a seasoned federal government attorney, but with a passion to challenge the government and fight on behalf of those citizens that have volunteered to serve as members of the military, federal civilian employees, or contractors.

Luke began his career as a Judge Advocate in the U.S. Army in 2006, first serving in various positions with the 8th Army in South Korea, to include serving as a prosecutor on all levels of criminal matters.  In 2009, Luke was stationed in Wiesbaden, Germany, where he served as the Chief of Justice for the 1st Armored Division.  The division deployed to Baghdad, Iraq, for the entirety of 2010, where Luke served as the Chief of Justice, overseeing the initial investigation and charging of a high-profile case involving the extensive harvesting and unauthorized distribution of classified information.

In 2011, Luke transitioned to serving as the Brigade Judge Advocate at the 66th Military Intelligence Brigade, Intelligence and Security Command.  That unit served as the Army’s intelligence and contribution to the European theater.  In that role, Luke advised the command on all intelligence and security matters, including counterintelligence, human intelligence, and access to classified information.  He transitioned to a civilian attorney with the brigade in 2014 and served in that position until 2020.  In 2015, Luke deployed as a civilian attorney to Bagram Airfield in Afghanistan to serve as the National Security Law attorney for Task Force – Observe, Detect, Identify, Neutralize (Task Force ODIN).  Luke accepted the position of National Security Attorney with U.S. Army Futures Command in Austin, Texas, in 2020.  In that position, he continued to advise on issues related to intelligence and security, with a focus on the best ways to legally protect the critical technologies being developed within the command.

Luke graduated from Luther College in 2001 and the University of Minnesota Law School in 2004, having spent time studying as a visiting student at Uppsala Universitet in Sweden and the William S. Richardson School of Law at the University of Hawaii.  In 2020, Luke was selected for and attended the inaugural class at the Technology and Law Academy through the University of Maryland’s Applied Research Laboratory for Intelligence and Security. Luke is admitted to practice law in Minnesota.

John McGuire

John is an incredibly talented attorney who brings an array of experience and perspective from both the public and private sectors.

Prior to John starting his career as an active duty Judge Advocate in the Army in 2012, John graduated from Ripon College in Ripon, WI where he commissioned through the college’s ROTC program as a Distinguished Military Graduate, finishing 121 out of 4,089 cadets nationwide. He then graduated from DePaul University College of Law in Chicago, IL in 2011.  John entered active duty in 2011 as an Armor officer, completing invaluable time as a platoon leader and executive officer at Fort Benning, GA.

John served as an active duty Judge Advocate until 2017, and continues to serve as a Major in the Reserves. In six years as an active duty Judge Advocate, he had already built a Corps-wide reputation for his zealous representation for his clients, adaptability, and commitment to embodying the JAG Corps motto: “Soldier first, lawyer always.”  John was the epitome of a broadly-skilled Judge Advocate who fully emersed himself in a variety of positions, excelling at every position.  John’s experience includes time as both a prosecutor and defense attorney at Fort Benning, GA and Fort Drum, NY, respectively.  John’s legal prowess and litigation expertise earned him a special appointment as the acting Trial Counsel to the 75th Ranger Regiment, where he handled all matters rising to the level of nonjudicial punishment and court-martial.  John also served as the Operational Law Attorney and Rule of Law Advisor for the 10th Mountain Division during its 2015 deployment to Eastern Afghanistan, and John’s latest role was serving as the National Security and Military Law Attorney for all of FORSCOM, headquartered at Fort Bragg, NC, specializing in high-profile investigations across FORSCOM.

In addition to serving in an “of counsel” role in the firm since 2019, John’s career as a civilian attorney has allowed him to specialize and excel in matters of labor and employment law.  He has served as in-house counsel for multiple Fortune 500 companies, specializing in not only labor and employment matters, but investigations and regulatory compliance. John is admitted to practice law in Wisconsin, Illinois, and the Federal Court of Claims.

Mark J. Oppel – Of Counsel

Mark J. Oppel has nearly twenty years of experience working on high-profile cases within the Department of Defense and the U.S. Army; Mark offers a unique global perspective to his clients and the firm. Mark retired from the

U.S. Army as a Lieutenant Colonel. He continued to serve his country as a GS-15 focusing on national security contracts such as helping negotiate the contracts required to create Army Futures Command. In short, Mark is committed to helping military personnel and civilians.

As an expert in Government acquisition, federal compliance, and litigation, Mark applies strategic yet practical thinking to help clients succeed in the Government and commercial marketplace. Mark guides clients in critical decision-making on complex statutes and regulations, delivering results, simplifying processes, increasing profitability, and enabling business relationships with the Government. Mark focuses on Entrepreneurial Business Law, Government Contracts including FAR and non-FAR contracts, Business Formation and Development, National Security Law, Cyber Law, Military Law, False Claims Act, and FOIA.

Mark holds a Master of Laws in Military Law from The Judge Advocate General’s Legal Center & School. He received his Juris Doctor from the University of Oklahoma College of Law and his Bachelor of Science in Business from Oklahoma State University. He is licensed to practice law in Texas, Oklahoma, and Missouri. Mark has received extensive training throughout his military and legal career, including advanced fiscal and government contract law, national security law, intelligence law, federal litigation, and federal employment law.

Born on a wheat and cattle farm in Western Oklahoma, Mark is an avid outdoorsman. He loves to fish, hunt, hike, ski, and golf. Mark is dedicated to being a soccer dad, supporting his church, and helping entrepreneurs and Veterans succeed in their ventures. Mark also helps numerous youth and nonprofit organizations, including Untrafficked and Refuge City, organizations dedicated to supporting victims of child sex trafficking. He has a passion for world travel, experiencing new cultures, wine tasting, and spending time with his wife Sarah and his four sons, Kilian, Zachary, Luke, and Owen. Mark is admitted to practice law in Oklahoma, Texas, and Missouri.


Yolande Liddy

Yolande joined the National Security Law Firm in 2019. Prior to working as a paralegal,, Yolande worked on Wall Street with a focus on international banking. Yolande started her paralegal career working on class action lawsuits. Yolande’s trial expertise includes both state and federal cases such as complex medical malpractice claims, personal injury claims, workers compensation claims, and criminal record expungements. Her almost four decades of experience on a wide range of cases provides her with a unique skill set that sets her apart from her peers. This invaluable experience assists the National Security Law Firm’s attorneys in obtaining great results for their clients both in federal court as well as administrative hearings. In short, her experience as a litigation specialist is unparalleled and provides the National Security Law Firm with a unique advantage.

Alicia McCray

Alicia is a US Army Veteran with over 13 years of JAG Corps and paralegal experience, wherein she obtained the rank of Sergeant First Class (SFC). After leaving the JAG Corps, Alicia worked at Fort Hood’s MEB/PEB office.  In short, her dedication to serving our veterans is unparalleled. She has a comprehensive background in medical evaluation boards, the Department of Veterans Affairs disability and compensation claims, military justice, administrative law, legal assistance, and detention operations. Additionally, Alicia possesses extensive knowledge in victim’s rights advocacy, resiliency training, and forensic psychology.

During her time in the Army, she served in several locations in the United States, Italy, and Afghanistan. As a result, she thoroughly understands NATO operations and operational law in deployed environments. Alicia also served as Military Science Instructor for US Army ROTC cadets. She also served as the Non-Commissioned Officer-In-Charge (NCOIC) while at the 470th Military Intelligence Brigade, where she was the senior enlisted person responsible for all legal actions in the Brigade. During her career, Alicia received multiple awards for outstanding performance and professionalism. Her career is supported by a Masters of Art in Criminal Justice Administration and a Masters of Philosophy in Philosophical Psychology. Currently, Alicia is Forensic Psychology Doctoral Candidate.

The military training and experience provide her with the necessary tools to be a true asset to the National Security Law Firm.

Nicolette Lewandowski

Nicolette (Nicki) works in our Global Entry and TWIC unit, helping our clients gather the documents we need for a successful appeal. Nicki is an alumni of the Ohio State University where she studied criminology and political science. She went on to graduate from the Blake McDowell School of Law at the University of Akron. During her time in law school, Nicki was a member of the Akron Law Trial Team with whom she competed in litigation against other law schools in the country. Nicki also worked at her county’s Prosecutor’s Office in both the general felony and major trial units. She had also worked for a private law firm specializing in criminal defense. In both capacities, Nicki was responsible for writing various motions, appeals, and assisting in prepping for trials. Outside of work, Nicki enjoys being outdoors and hanging out with her friends, her husband, and her pitbull-husky mix, Kaiya.

Cara Sliger

Cara Sliger is a former paralegal Non-Commissioned Officer (NCO), Staff Sergeant, in the United States Army JAG Corps.  Her training and experience in the Army JAG Corps provide her with a unique understanding of the military justice system as well as all types of administrative law issues, such as military discharge upgrades.

Cara began her Army career as a paralegal for the 902nd Military Intelligence Group, under the command of the United States Army Intelligence and Security Command, where she focused on counterintelligence investigations and all aspects of the Uniform Code of Military Justice. She was routinely assisting the 902d Intelligence Law Attorney with advising commanders on recommendations for the permanent or temporary suspension of an individual’s security clearances.

After her experiences at the 902d, she PCS’d to the Great Place to work at III Armored Corps, United States Army Forces Command, where she focused on courts-martial, non-judicial punishment, administrative investigations, and reprimands of the military justice system with involvement in several high-profile cases.

Cara’s extensive experience in the military makes her the perfect fit for the National Security Law Firm.

Stephanie Gangloff

Stephanie began her Army career at 1st Armored Division, Fort Bliss, Texas as the Battalion Paralegal Specialist.  Based on her work performance and attention to detail, she was individually selected by the the Office of the Staff Judge Advocate, to work as a Criminal Law Paralegal Specialist. After Fort Bliss, Stephanie deployed to Bagram, Afghanistan. She experienced first hand the challenges of working in an austere environment, which enables her to relate with many of the National Security Law Firm’s clients.  Her commitment to excellence resulted in her being the 160th Signal Brigade legal office’s NCOIC.

Upon successful completion of her deployment, Stephanie was assigned to the 902nd Military Intelligence Group where she again served as the NCOIC. While at the 902d MI Group, Stephanie worked with Brett, who was the Intelligence Law attorney for the unit.  Based upon her stellar performance she temporarily served as NCOIC of 704th Military Intelligence Brigade, and the 780th Military Intelligence Brigade.  In short, she has experiencing supporting many of the Nation’s intelligence organizations.

Stephanie’s education includes a Bachelor of Art degree with a major in Sociology with a concentration in Criminal Justice and a minor in Counseling from Carlow University. Additionally, she also has a Paralegal Certificate from the Community College of Allegheny County.

Janet Schnell

Janet is a US Army Veteran with over 20 years with five years as a firefighter and 15 years in the JAG Corps as a paralegal and court reporter, where she retired at the rank of Sergeant First Class (SFC). During her time in the Army, she served in several locations in the United States, Korea, Iraq, and Afghanistan. 

While serving as a court reporter, Janet was responsible for transcribing court hearings, assembling evidence, and distributing the casefile to the appropriate entities. While serving as a paralegal, Janet was responsible for speaking to witnesses, gathering evidence, drafting memorandums, notarizing documents, and prepping the case and attorney to go to court.

While serving in the Army, Janet has been stationed at Fort Rucker (Fort Novosel) as a firefighter with the 6th MP Detachment, Yongsan, South Korea as a court reporter with the 8th Army, Fort Hood (Fort Cavazos) as a court reporter, Fort Gordon (Fort Eisenhower) as a brigade paralegal with the 15th Regimental Signal Brigade, Fort Riley as a court reporter, Fort Sam Houston as a senior paralegal/court reporter, Fort Riley as a senior court reporter. Janet has also been deployed to Camp Liberty, Iraq as a court reporter and to Bagram Air Base, Afghanistan as security personnel.

Janet has obtained two degrees, a Bachelor of Science with a major in Criminal Justice and an Associates Degree in Management from Excelsior College. While in the Army, Janet obtained 2 ARCOM, 2 AAM, 1 ASUA, 6 AGCM, 1 NDSM, 1 ACM-CS, 2 ICM-CS, 1 GWTSM, 1 KDSM, 2 NOPDR, 1 ASR, 2 OSR, 1 NATOMDL, 1 COA; WLC, ALC, SLC; Advanced Court Reporter Course; Redictation Course; Master Resilience Training; Combat Life Savers Course; Hygiene/Sanitation Course; and Court Reporter Course. 

The military training and experience provide her with the necessary tools to be a valuable asset to the National Security Law Firm.


If you are appealing a security clearance determination, it is imperative that you obtain experienced legal representation. Doing so will provide you with the best opportunity to obtain or maintain your clearance.

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