Legal Guide
What Is a Security Clearance?
A security clearance is not a privilege. It is a determination by the federal government that you can be trusted with classified national security information. Understanding how that determination is made, what can threaten it, and how to protect it is the starting point for anyone working in or entering the cleared workforce.
Matthew Thomas, Esq.
Former Marine Judge Advocate · 2× USMC Defense Counsel of the Year
Overview
A security clearance is a determination by the federal government that a person is eligible to access classified national security information. It is not a license or a certification. It is a trust determination: the government has investigated your background and concluded that you are reliable, trustworthy, and loyal enough to be given access to information whose unauthorized disclosure could damage national security.
According to the Office of the Director of National Intelligence (ODNI), approximately 3.6 million people in the United States hold active security clearances. That number includes active-duty military members, federal civilian employees, and government contractors working in defense, intelligence, and national security. For many of these people, the clearance is their career. A cybersecurity contractor with a Top Secret/SCI clearance earns $150,000 to $250,000 annually. Losing that clearance does not just cost a job. It removes you from an entire professional field.
The clearance process begins when your employer submits a request for investigation to the Defense Counterintelligence and Security Agency (DCSA). You complete the SF-86 (Standard Form 86), an 80-to-100-page questionnaire covering your employment history, complex drug misconduct, financial situation, criminal record, drug use, mental health treatment, and more. DCSA conducts the background investigation. An adjudicator reviews the results against 13 adjudicative guidelines under Security Executive Agent Directive 4 (SEAD 4) and determines whether you are eligible for a clearance.
If the adjudicator finds disqualifying information, you receive a Statement of Reasons (SOR) and have the opportunity to respond, present mitigation evidence, and in most cases request a hearing before a Defense Office of Hearings and Appeals (DOHA) administrative judge. This is where a security clearance attorney becomes relevant. Matthew Thomas handles every stage of this process, from SF-86 consultation through DOHA hearing and appeal.
A security clearance is not a privilege. It is a trust determination. Protect it accordingly.Matthew Thomas, Esq. — What Is a Security Clearance?
What You Need to Know
Read this before you do anything.
01
What is a security clearance?
A security clearance is the federal government's determination that you can be trusted with classified national security information. The three primary levels are Confidential, Secret, and Top Secret. Each level corresponds to the sensitivity of the information you are authorized to access. Some positions also require access to Sensitive Compartmented Information (SCI), which adds additional investigation and adjudication requirements beyond Top Secret.
02
Security clearance levels: Confidential, Secret, Top Secret, and SCI
Confidential clearance authorizes access to information whose disclosure could cause damage to national security. Secret clearance covers information whose disclosure could cause serious damage. Top Secret covers information whose disclosure could cause exceptionally grave damage. SCI access is a designation above Top Secret that compartments information into specific programs. Each level requires progressively deeper background investigation. Confidential and Secret clearances require a Tier 3 investigation. Top Secret requires a Tier 5 investigation. SCI access may require additional polygraph examination depending on the agency.
03
Who needs a security clearance?
Active-duty military members in positions requiring access to classified information. Federal civilian employees at defense, intelligence, and national security agencies. Government contractors whose work requires handling classified materials. Intelligence community personnel. The specific clearance level required depends on the position and the classification of the information involved.
04
How the security clearance process works
Step 1: Your employer submits a request for investigation. Step 2: You complete the SF-86. Step 3: DCSA conducts the background investigation, including interviews with you, your references, neighbors, and employers. Step 4: An adjudicator reviews the investigation against the 13 guidelines in SEAD 4. Step 5: You are either granted a clearance or issued a Statement of Reasons identifying disqualifying information. If issued an SOR, you can respond, present evidence, and request a DOHA hearing.
05
What can disqualify you from a security clearance?
The 13 adjudicative guidelines under SEAD 4 define the categories of potentially disqualifying conduct: allegiance to the United States, foreign influence, foreign preference, sexual behavior, personal conduct, financial considerations, alcohol consumption, drug involvement, psychological conditions, criminal conduct, handling protected information, outside activities, and misuse of information technology. Financial problems (Guideline F) are the single most common reason for denial. Drug involvement (Guideline H), foreign influence (Guideline B), and personal conduct (Guideline E) follow. Each guideline includes specific mitigating conditions.
06
What happens during a background investigation?
The investigator reviews your SF-86 and then conducts interviews: with you (the Subject Interview), with your listed references, with former employers, with neighbors, and with others who can speak to your character and reliability. They review court records, financial records, and law enforcement databases. For Top Secret investigations, the scope is broader and the interviews are more extensive. The investigation results go to an adjudicator who evaluates the whole-person concept: the totality of your record, not a single issue in isolation.
07
How long does a security clearance last?
Security clearances are subject to periodic reinvestigation. Under the current Continuous Evaluation program, DCSA monitors cleared individuals through automated record checks between formal reinvestigations. The traditional reinvestigation cycle is 10 years for Secret and 5 years for Top Secret. During a reinvestigation, the SF-86 is completed again and the investigator re-examines your record for any changes since the last investigation. Issues that arose and were not reported can create problems at reinvestigation.
08
What to do if your clearance is denied or revoked
A denial or revocation is not final. You receive a Statement of Reasons identifying the disqualifying information. You have 20 days to elect a DOHA hearing and 30 days to file a substantive response. The response and hearing are your opportunity to present mitigation evidence. Matthew Thomas handles clearance denial and revocation defense from the SOR through DOHA hearing and appeal. If your clearance is adjudicated by NSA rather than DCSA, the process is different. NSA operates its own adjudication office with its own appellate body, the Access Appeals Panel (AAP).
In This Guide
Section 01
What a Security Clearance Actually Is
A security clearance is a formal determination by the federal government that a person can be trusted with access to classified national security information. It is not a license, a credential, or a background check result. It is an eligibility determination made by a federal adjudicative authority after reviewing a person's history, character, finances, complex drug misconduct, and other factors against a set of adjudicative guidelines.
The determination is made under the framework established by the Security Executive Agent Directive 4 (SEAD-4), which outlines 13 adjudicative guidelines covering areas like financial issues, complex drug misconduct, criminal conduct, drug use, and psychological conditions. Adjudicators weigh both disqualifying conditions and mitigating factors to determine whether granting or continuing a clearance is consistent with the national security interests of the United States.
The short version: a clearance is not automatic, it is not permanent, and it can be revoked. The government's determination is that you, specifically, can be trusted, and that determination can change.
Section 02
Clearance Levels: Confidential, Secret, Top Secret, and SCI
Federal security clearances are issued at three levels: Confidential, Secret, and Top Secret. Each level corresponds to the classification level of information the holder may access. There is also a separate designation (Sensitive Compartmented Information, or SCI) that grants access to specific intelligence programs beyond the Top Secret baseline.
Confidential is the baseline level and requires a National Agency Check with Local Agency Checks (NACLC). Secret is the most common clearance level for military members and federal contractors, requiring a more thorough investigation. Top Secret requires a Single Scope Background Investigation (SSBI) and a significantly more intensive review of the applicant's history.
Top Secret/SCI is required for positions involving access to Sensitive Compartmented Information, meaning classified intelligence sources and methods. Some TS/SCI positions also require a polygraph examination (counterintelligence scope or full scope, depending on the agency). NSA and CIA positions frequently require polygraph.
SCI Is Not a Clearance Level
SCI is an access designation, not a clearance level. A person holds a Top Secret clearance and is then granted SCI access to specific programs or compartments. Losing SCI access is distinct from losing the underlying clearance.
Section 03
How the Investigation Process Works
The clearance process begins with the SF-86, the Standard Form 86, Questionnaire for National Security Positions. This is a comprehensive disclosure document covering 10 years of personal history: residences, employment, education, foreign travel, complex drug misconduct, financial history, criminal history, drug use, mental health treatment, and more. The SF-86 is submitted through the Electronic Questionnaires for Investigations Processing (e-QIP) system.
After submission, DCSA (Defense Counterintelligence and Security Agency) conducts the investigation. Depending on the clearance level, this involves automated records checks, financial records review, criminal history search, and personal interviews with references, former employers, neighbors, and the applicant. The investigation produces a raw investigative file that is forwarded to the adjudicative authority.
The adjudicator, working at DCSA or at the applicant's specific agency, reviews the file against the SEAD-4 guidelines and makes an eligibility determination. If the determination is favorable, clearance eligibility is granted. If concerns exist, the adjudicator may issue a Statement of Reasons (SOR) setting out the specific disqualifying conditions and giving the applicant an opportunity to respond.
Section 04
What Can Threaten a Security Clearance
Any of the 13 SEAD-4 adjudicative guidelines can be the basis for a clearance denial or revocation. The most common issues in practice are: financial problems (significant debt, bankruptcies, pattern of financial irresponsibility), drug use (including marijuana in states where it is legal under state law), criminal conduct (arrests, charges, or convictions), complex drug misconduct and foreign financial interests, and psychological conditions that raise concerns about judgment or reliability.
Less common but equally serious: dishonest or deceptive conduct (including omissions or misrepresentations on the SF-86), outside activities or conflicts of interest, and security violations. Sexual behavior that creates vulnerability to coercion has historically been an adjudicative concern, though the weight given to consensual adult conduct has changed significantly over the past decade.
The most important principle in the SEAD-4 guidelines is the whole-person concept: adjudicators do not mechanically deny clearances based on the presence of a disqualifying condition. They weigh the entire record, including mitigation. Recency, severity, rehabilitation, the circumstances surrounding the conduct, and evidence of reform all matter. A person who had serious financial problems five years ago but has demonstrated sustained recovery is in a different position than a person with ongoing financial issues.
Marijuana Use and Federal Clearances
State legalization has not changed federal adjudicative standards. Marijuana use (even in states where it is fully legal) must be disclosed on the SF-86 if it falls within the applicable time windows. Failure to disclose is a separate and more serious problem than the underlying use. See our guide on security clearance and marijuana for the full analysis.
Section 05
The Statement of Reasons and Your Right to Respond
If the adjudicator finds disqualifying conditions, they issue a Statement of Reasons: a formal document identifying the specific concerns and setting out the adjudicative guidelines at issue. The SOR is not a final revocation or denial. It is an invitation to respond.
Upon receiving an SOR, you have a set number of days to submit a written response. The response is your opportunity to address each allegation, provide context, submit mitigating evidence, and make the case that the disqualifying conditions are outweighed by your overall record. A poorly framed SOR response can close doors on appeal. A well-framed response can resolve the matter without a hearing.
If the SOR response does not resolve the matter, the case may proceed to a hearing before a DOHA administrative judge (for DCSA cases) or to a similar proceeding at the relevant agency. The administrative judge hears testimony and reviews documentary evidence before issuing a written decision. That decision can be appealed to the Personnel Security Appeals Board.
Do Not Respond to an SOR Without Counsel
The SOR response is the foundation for everything that follows, including any appeal. Responding without an attorney, or responding too quickly without fully understanding the allegations, is one of the most common and most costly mistakes in security clearance defense. Call before you write anything.
Related Services
Related Practice Areas
Security Clearance Defense
SOR response, DOHA hearings, NSA adjudications, and DCSA appeals.
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SOR / SIR Response
Statement of Reasons and Supplemental Information Requests handled from first notice through appeal.
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Security Clearance Appeals
DOHA administrative hearings and Personnel Security Appeals Board proceedings.
Learn More →
NSA Clearance Defense
NSA runs a separate adjudication process. Matthew has worked NSA cases extensively.
Learn More →
Common Questions
Frequently Asked Questions
Processing times vary by clearance level and current DCSA workload. Secret clearances have historically processed in 3-6 months. Top Secret investigations can take 9-18 months or longer. Cases involving complex drug misconduct, financial complexity, or other adjudicative concerns take longer. Once a concern is identified and an SOR is issued, the timeline extends further depending on whether the matter resolves at the response stage or proceeds to a DOHA hearing.
It depends. In some cases, interim clearance eligibility is granted while the full investigation is pending. In others, particularly when an SOR has been issued or a clearance has been suspended, access is revoked pending the outcome. Your employer's FSO and the specific program security officer for your contract determine practical access during the proceedings.
A denial occurs when an initial application for clearance eligibility is not granted. A revocation occurs when an existing clearance that has already been granted is rescinded. The procedural tracks are similar (SOR, response, potential hearing, appeal) but the circumstances differ. Revocations often carry more immediate employment consequences because the person is already in a cleared position.
No. Attorneys cannot guarantee outcomes in any legal proceeding, and anyone who promises a specific outcome in a clearance matter should be approached with skepticism. What an experienced security clearance attorney does is ensure that your response is framed correctly, your evidence is presented completely, and your case is built in the way most likely to succeed at each stage of the process.
Two Ways to Start
Questions About Your Specific Situation?
This guide covers the general principles. Every case has unique facts. Need ongoing support? Matthew Thomas offers a free 15-minute call. No charge, confidential.
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