The N-400 naturalization application contains 50-plus questions designed to screen out applicants who fail the "good moral character" requirement under INA § 101(f), the continuous residence requirement under INA § 316(b), or the attachment-to-the-Constitution requirement under INA § 337(a). USCIS adjudicators run each N-400 against multiple federal databases — FBI criminal history, IRS tax history, Selective Service records, state child support enforcement records, and the CBP travel history — and any mismatch between the application and the database hits is treated as a "red flag" that triggers additional scrutiny, a Request for Evidence, or a denial. The 12 most common red flags, listed below, account for the majority of N-400 denials and continuances issued by USCIS each year. Some can be cured before filing; others are permanent bars that disqualify the applicant regardless of how much time has passed. Identifying and addressing red flags before filing can save the applicant a $725 filing fee, months of waiting, and the public stigma of a naturalization denial.
Selective Service Non-Registration
Under the Military Selective Service Act (50 U.S.C. § 3802), every male U.S. citizen and male lawful permanent resident between the ages of 18 and 26 must register with the Selective Service System within 30 days of his 18th birthday (or within 30 days of becoming an LPR, if that occurs after age 18). Failure to register is a felony punishable by up to five years in prison and a $250,000 fine, although prosecutions are essentially nonexistent. For naturalization purposes, the failure to register is not a permanent bar but is treated as evidence against good moral character under 8 CFR § 316.10(b)(2). The regulation requires the applicant who failed to register to provide a written explanation under penalty of perjury stating that he did not "knowingly and willfully" fail to register — that is, that his failure was not intentional. The "knowing and willful" standard means the applicant must have actually known of the requirement and chosen not to comply; lack of knowledge, despite the legal presumption of knowledge, can still be argued.
Male applicants who arrived in the U.S. after their 26th birthday are not required to register, but they must still answer the Selective Service question on the N-400. The applicant must demonstrate that he was unaware of the registration requirement and that his failure was not intentional, supported by evidence such as proof that he was unaware of the requirement (educational records showing lack of English-language exposure, evidence that he lived in a country where the U.S. Selective Service System was not advertised, or evidence that his immigration attorney did not advise him of the requirement). The Status Information Letter from the Selective Service System, which confirms non-registration, is required for any male applicant who was required to register but did not. USCIS adjudicators have discretion to approve the N-400 despite the non-registration if the explanation is credible, but multiple or compounding red flags (non-registration plus tax issues, for example) make the approval less likely. Registration is still possible after age 26 only with the Selective Service's permission, which is rarely granted.
Tax Debts, Unfiled Returns, and Payment Plans
Tax problems are the second most common cause of N-400 delays and denials. USCIS adjudicators check the applicant's IRS file through the Federal Tax Information program, which provides direct access to IRS records. Applicants who have unfiled tax returns, unpaid tax debts, or no IRS payment plan in place will be continued or denied. The N-400 application specifically asks whether the applicant has ever failed to file a federal, state, or local tax return that he was required to file, and whether he owes any overdue tax debt. An affirmative answer requires the applicant to provide documentation showing that the issue has been resolved or is in active resolution. For unfiled returns, the applicant must file the missing returns and provide copies to USCIS; for unpaid debts, the applicant must establish an IRS payment plan (Form 9465) and provide proof of current payments.
The standard USCIS applies is not just that the debt exists but whether the applicant has acted responsibly to address it. An applicant with a $30,000 tax debt who has filed all returns, has an active payment plan, and has made every scheduled payment will typically be approved — the debt itself is not a permanent bar to good moral character. An applicant with the same debt who has not filed the missing returns, has not established a payment plan, or has missed scheduled payments will be denied. State and local tax debts are treated similarly, though USCIS's access to state tax records varies. Applicants who have been audited or who have been the subject of IRS collection activity should consult with a tax attorney before filing the N-400, because the underlying tax issue may itself be a problem (such as a finding of fraud or negligence that reflects on good moral character). Applicants who owe more than $50,000 in federal tax debt may also face passport revocation or denial under 26 U.S.C. § 7345, which can complicate the travel history portion of the N-400.
Long Trips Absent and Continuous Residence
Under INA § 316(b), absences from the United States of more than six months but less than one year during the statutory period create a rebuttable presumption of a break in continuous residence. The applicant can rebut the presumption under 8 CFR § 316.5(c)(1)(ii) by showing that he did not disrupt his U.S. residence — typically through evidence of continued U.S. employment, family in the U.S., retention of a U.S. residence, and no employment abroad during the absence. A single trip of one year or more generally breaks continuous residence and resets the statutory clock, unless the applicant filed Form N-470 (Application to Preserve Residence for Naturalization Purposes) before the trip and the trip was for qualifying government, religious, or corporate employment.
The six-month presumption is one of the most frequently invoked N-400 red flags. A single trip of 185 days triggers the presumption, and the applicant must produce evidence of continued U.S. ties during the absence — pay stubs showing continued U.S. payroll, leases showing retention of a U.S. residence, school records showing children remained in U.S. schools, and bank statements showing continued U.S. financial activity. The applicant should be prepared to explain the purpose of the trip (such as caring for an ill parent abroad, a temporary foreign assignment with a U.S. employer, or religious mission work) and to demonstrate that the trip was always intended to be temporary. Trips of less than six months do not trigger the presumption but are still scrutinised — a pattern of frequent extended trips (such as four 5-month trips in five years) can raise concerns about whether the applicant has actually been residing in the U.S. The physical presence requirement (913 days for the five-year rule, 548 days for the three-year rule) is independent of continuous residence and must be satisfied even if the continuous residence presumption is successfully rebutted.
Arrests, Convictions, and CIMT Bars
Criminal history is the single most scrutinised section of the N-400. The application asks whether the applicant has ever been arrested, cited, detained, or charged with any offense, regardless of disposition. Every arrest must be disclosed, even if the case was dismissed, expunged, sealed, or diverted to a diversion program — the only exception is a traffic citation that did not involve drugs or alcohol and resulted in a fine of less than $500. The applicant must bring certified court dispositions for every disclosed incident to the naturalization interview. Failure to disclose an arrest is itself a basis for denial under the "false testimony" rule of INA § 101(f)(6), which treats any lie under oath during the naturalization process as a permanent bar to good moral character.
The most serious criminal red flag is a conviction for a Crime Involving Moral Turpitude (CIMT). Under INA § 101(f)(3), a CIMT conviction during the statutory period (5 years for most applicants, 3 years for marriage-based applicants) creates a presumption against good moral character. Common CIMTs include theft, fraud, embezzlement, assault with intent to commit serious bodily injury, child abuse, and most sex offenses. A single CIMT conviction with a maximum possible sentence of one year or less, where the actual sentence served was six months or less, may fall under the "petty offense exception" of INA § 212(a)(2)(A)(ii)(II), which waives the inadmissibility consequences but does not necessarily eliminate the good moral character issue. Two or more CIMT convictions are a permanent bar with limited exceptions. Aggravated felonies under INA § 101(a)(43) — which include murder, rape, sexual abuse of a minor, drug trafficking, firearms trafficking, money laundering over $10,000, theft offenses with a sentence of one year or more, and certain fraud offenses with loss over $10,000 — are permanent bars to naturalization under INA § 101(f)(8) and trigger mandatory deportation under INA § 238(b). DUI convictions are not CIMTs but two or more DUIs within the statutory period create a presumption of alcohol abuse, which in turn creates a good moral character issue under 8 CFR § 316.10(b)(3) — USCIS may require a substance abuse evaluation as a condition of approval.
False Claims to Citizenship and Voting Violations
Two red flags are permanent bars to naturalization with very limited exceptions: false claims to U.S. citizenship and voting in a U.S. election in violation of law. Under INA § 101(f)(9) and 18 U.S.C. § 911, any alien who falsely represents themselves as a U.S. citizen for any purpose or benefit under federal or state law is permanently barred from good moral character, and is also deportable under INA § 237(a)(3)(D). The bar applies regardless of whether the false claim was made during the statutory period or earlier, and regardless of whether the applicant was prosecuted for the false claim. Common scenarios include checking "U.S. citizen" on an I-9 employment verification form, claiming U.S. citizenship to register to vote, claiming U.S. citizenship to obtain a U.S. passport, or claiming U.S. citizenship to receive a federal or state benefit. The narrow exceptions, codified at INA § 101(f)(9) and as amended by the Child Citizenship Act of 2000, apply only to applicants whose parents were U.S. citizens, who permanently resided in the U.S. before age 16, and who reasonably believed they were U.S. citizens at the time of the false claim.
Voting in violation of law under 18 U.S.C. § 611 — which prohibits aliens from voting in any election for federal office — is similarly a permanent bar to good moral character under INA § 101(f)(9). The bar applies to voting in federal elections (President, Vice President, U.S. Senator, U.S. Representative) and most state and local elections, regardless of whether the applicant knew the voting was unlawful. The bar also applies to false claims of U.S. citizenship made in connection with voter registration, regardless of whether the applicant actually voted. The practical consequence is that any N-400 applicant who has ever registered to vote or voted in a U.S. election must disclose this on the application and must understand that the disclosure will likely result in denial and may trigger removal proceedings. Some states (California, New York, and others) have moved to allow non-citizen voting in certain local elections, but federal law still prohibits non-citizens from voting in federal elections, and USCIS has taken the position that voting in any local election where non-citizen voting is not specifically authorised by state law is a violation of INA § 101(f)(9).
Child Support, Warrants, and Gambling Offenses
Failure to meet family obligations is a frequently overlooked N-400 red flag. Under 8 CFR § 316.10(b)(3)(iii), an applicant who has failed to support dependents as required by court order or written agreement is presumed to lack good moral character. The applicant must provide evidence of current payment compliance — typically pay stubs or bank statements showing the most recent 6 to 12 months of payments — and any arrearage must be addressed through a payment plan or a court-ordered modification. Even where there is no court order, USCIS may consider evidence of voluntary support provided to minor children when evaluating good moral character. Applicants who have been the subject of state child support enforcement actions should provide certified copies of the most recent child support order and proof of current payment status.
Outstanding warrants — criminal, civil, or for failure to appear — are an absolute bar to naturalization because the applicant cannot demonstrate good moral character while subject to an unresolved warrant. USCIS checks the National Crime Information Center (NCIC) database for warrants, and any warrant must be resolved before the N-400 is approved. The resolution typically requires the applicant to appear in the issuing court, address the underlying charge, and obtain a certified disposition. Gambling offenses, while less common than other red flags, can be CIMTs if they involve fraud or deceit (such as bookmaking or operating an illegal gambling operation) and can raise good moral character concerns even when charged as misdemeanors. Lawful gambling (casino visits, lottery tickets, sports betting where legal) is not a red flag, but USCIS may scrutinise an applicant with significant gambling activity if there are indications of financial irresponsibility — large unexplained debts, multiple bankruptcies, or reliance on public benefits despite income. The pattern that raises red flags is typically financial misconduct — tax debt, unpaid child support, gambling losses, and bankruptcy all converge on the good moral character question.
Fixing Red Flags Before You File
Many N-400 red flags can be cured before filing, often with substantial effort but with significant payoff in the form of a smoother application process. The first step is a self-audit: request your IRS tax transcripts for the past five years (free at irs.gov), your CBP travel history (free through the CBP I-94 website), your Selective Service registration record (free at sss.gov), your FBI criminal history record (through a fingerprint-based background check), and your state child support payment record. These are the same records USCIS will check, and reviewing them in advance allows you to identify discrepancies, address omissions, and prepare explanations. If you have unfiled tax returns, file them now — even if you cannot pay the tax owed, filing the returns eliminates the "failure to file" issue and allows you to set up a payment plan. If you have outstanding warrants, contact a criminal defense attorney and resolve them before filing the N-400.
The second step is to evaluate the timing of your filing. If your statutory period ends on 1 July 2025 but you have a CIMT conviction from August 2020, waiting to file until 1 August 2025 (after the conviction falls outside the statutory period) can be the difference between approval and denial. The statutory period for good moral character is generally the five years immediately preceding the filing date (three years for marriage-based applicants), and conduct outside that period is generally not considered — though some aggravated felonies and certain other offenses are permanent bars regardless of when they occurred. The third step is to consult with an immigration attorney before filing if you have any red flag. An hour of consultation ($200 to $500) can identify issues that would otherwise cause a denial, save the $725 filing fee, and avoid the public record of a denial that could affect future applications. Many immigration attorneys offer a free or low-cost N-400 eligibility screening, and non-profit organisations such as Catholic Charities, the International Rescue Committee, and local immigrant advocacy groups provide free or low-cost naturalisation assistance for low-income applicants. For more on the broader naturalisation timeline, see our N-400 application timeline and our physical presence guide.
Frequently asked questions
Yes. USCIS conducts fingerprint-based FBI background checks that return the full criminal history, including arrests and convictions that have been expunged, sealed, or dismissed after diversion. The expungement or sealing under state law does not erase the record for federal immigration purposes, and you must disclose the arrest and conviction on the N-400 regardless of the state disposition. Failure to disclose is itself a permanent bar under the "false testimony" rule of INA § 101(f)(6), even if the underlying offense would not have been a bar. Bring certified court dispositions for every disclosed incident — even if the case was expunged, the court can typically provide a certified copy of the disposition upon request.
You cannot register after age 26, but you can request a Status Information Letter from the Selective Service System that documents your non-registration, and you can submit a written explanation with your N-400 stating that your failure to register was not knowing and willful. The explanation should describe your circumstances at the time you should have registered — your age when you arrived in the U.S., your awareness of the registration requirement, your educational background, and any other factors showing you did not intentionally avoid registration. USCIS adjudicators have discretion to approve the N-400 despite non-registration, particularly if the explanation is credible and supported by evidence. The Status Information Letter is required for all male applicants who were required to register but did not, and the letter should be submitted with the N-400 application.
No. A tax debt alone is not a bar to naturalisation, provided you have filed all required returns and have an active IRS payment plan with current payments. USCIS is looking for evidence of financial responsibility, not the absence of debt. Bring to your interview copies of your filed returns, your Form 9465 payment plan agreement, and proof of your most recent 6 to 12 months of payments. If you owe more than $50,000 in federal tax debt, you may also face passport revocation or denial under 26 U.S.C. § 7345, which could affect your ability to travel and could complicate the continuous residence evaluation if you have made foreign trips while the passport was restricted. State and local tax debts are treated similarly — file the returns, set up a payment plan, and document your compliance.
For more, see our N-400 application timeline, our US citizenship interview guide, and our marriage to U.S. citizen naturalisation guide.
Last reviewed June 20, 2026. This article is informational and does not constitute legal, tax, or financial advice. Consult a qualified professional for guidance specific to your situation.