Federal law is the body of rules made by the national government of the United States under the Constitution, and it sits above state and local law wherever the two conflict. It governs specific subjects the Constitution assigns to Congress, reaches into criminal cases with a national dimension, and controls how certain civil disputes are decided. This explainer of federal law walks through where that authority comes from, when it displaces state rules, how cases enter the federal system, and what happens once they do.
Where Federal Authority Comes From
Congress’s powers are listed in Article I, Section 8 of the Constitution. The list includes collecting taxes, regulating commerce between states and with foreign nations, coining money, running the post office, providing for national defense, and setting uniform rules for naturalization and bankruptcy.1Constitution Annotated. Article I Section 8 – Enumerated Powers Anything not on that list was meant to stay with the states or the people.
The Necessary and Proper Clause, at the end of that same section, lets Congress pass laws needed to carry out its listed powers even when the Constitution doesn’t spell out every detail. The Supreme Court confirmed that flexibility in 1819 in McCulloch v. Maryland, holding that Congress can choose reasonable means to accomplish its constitutional duties.2Constitution Annotated. ArtI.S8.C18.1 Overview of Necessary and Proper Clause That’s how federal authority reaches subjects the framers never imagined, from internet regulation to air traffic control.
Backing all of it is the Supremacy Clause in Article VI, which declares that the Constitution and federal laws made under it are “the supreme law of the land.” State judges are bound by federal law even where it conflicts with their own state’s constitution or statutes.3Legal Information Institute. Article VI
When Federal Law Overrides State Law
The Supremacy Clause is enforced through a doctrine called preemption. It comes in two forms.
Express preemption is written into the statute itself. When Congress says “no state shall enforce any law inconsistent with this section,” there is no ambiguity about which rule controls.4Congress.gov. Federal Preemption – A Legal Primer
Implied preemption is harder to spot. Field preemption applies when federal regulation of an area is so thorough that Congress clearly intended to occupy the whole field, leaving no room for state rules. Conflict preemption applies when following both laws at once is physically impossible, or when the state law would obstruct what Congress was trying to achieve.4Congress.gov. Federal Preemption – A Legal Primer Immigration enforcement and drug scheduling generate constant disputes on this ground.
When a Case Becomes a Federal Case
Criminal Cases
A crime becomes federal when it involves a federal interest rather than a purely local one. Common triggers include conduct that crosses state lines, crimes on federal property such as military bases or national parks, offenses against federal officers, and violations of statutes rooted in Congress’s power to regulate interstate commerce. Robbing a federally insured bank is a federal crime even if the robber never leaves the county, because Congress used its commerce power to protect the banking system.
Because Congress has stretched federal criminal statutes to cover conduct that “affects” interstate commerce even indirectly, the same act can often be charged in either the state or the federal system.
Civil Cases
Federal courts hear civil lawsuits through two main gateways. Federal question jurisdiction covers any lawsuit that arises under the Constitution, a federal statute, or a treaty. Patent claims, antitrust suits, and constitutional due process claims all qualify.5Office of the Law Revision Counsel. 28 USC 1331 – Federal Question
Diversity jurisdiction applies when the parties are citizens of different states and more than $75,000 is at stake. For class actions, the threshold is $5,000,000.6Office of the Law Revision Counsel. 28 USC 1332 – Diversity of Citizenship A neutral federal court is meant to prevent home-court advantage when an out-of-state party might face local bias.
Common Categories of Federal Crimes
Federal criminal law is vast, but a handful of statutes account for a large share of prosecutions.
Racketeering. The Racketeer Influenced and Corrupt Organizations statute (RICO), at 18 U.S.C. §§ 1961–1968, targets people who participate in criminal enterprises. It covers a broad range of underlying crimes, including extortion, fraud, and drug trafficking, when they form a pattern of activity tied to an organization.7Office of the Law Revision Counsel. 18 USC Chapter 96 – Racketeer Influenced and Corrupt Organizations Convictions can bring asset forfeiture in addition to prison.
Drug offenses. The Controlled Substances Act, beginning at 21 U.S.C. § 801, is the national framework for regulating drug manufacturing, distribution, and possession. Congress based this authority on the flow of controlled substances through interstate commerce.8Office of the Law Revision Counsel. 21 USC Chapter 13 – Drug Abuse Prevention and Control Penalties escalate sharply with drug type and quantity.
Wire fraud. Under 18 U.S.C. § 1343, wire fraud covers any scheme to defraud that uses interstate communications, which in practice means almost any scam involving a phone call, email, or electronic transfer. The maximum is 20 years in prison, rising to 30 years and a $1,000,000 fine when the fraud targets a financial institution or a presidentially declared disaster.9Office of the Law Revision Counsel. 18 USC 1343 – Fraud by Wire, Radio, or Television
Computer crimes. The Computer Fraud and Abuse Act, 18 U.S.C. § 1030, criminalizes unauthorized access to protected computers, which the law defines broadly enough to include virtually any device connected to the internet. Penalties run from one year for basic unauthorized access up to 20 years for repeat offenders in national security cases.10Office of the Law Revision Counsel. 18 USC 1030 – Fraud and Related Activity in Connection With Computers
The Federal Court System
Federal cases begin in one of the 94 U.S. District Courts. These are the trial courts, where witnesses testify, juries are seated, and verdicts are delivered. Every state has at least one district; larger states have several.11United States Courts. About U.S. District Courts
Those 94 districts are grouped into 12 regional circuits, each with its own U.S. Court of Appeals. A thirteenth court, the Federal Circuit, has nationwide jurisdiction over specialized areas such as patent disputes and claims against the government.12United States Courts. About the U.S. Courts of Appeals Appeals courts don’t retry cases; they review whether the district court applied the law correctly.
The U.S. Supreme Court sits at the top. Losing parties can petition for a writ of certiorari, and the Court accepts roughly 100 to 150 of the more than 7,000 petitions it receives each year, typically taking cases that present significant constitutional questions or resolve splits between the circuits.13United States Courts. Supreme Court Procedures Its decisions bind every court in the country.
Separate specialized courts handle narrower disputes. Federal bankruptcy courts manage liquidation and reorganization under Chapters 7, 11, and 13; filing fees for a Chapter 7 case total $338.14United States Courts. Chapter 7 – Bankruptcy Basics The U.S. Court of Federal Claims hears lawsuits seeking money from the federal government, including contract disputes, military pay claims, tax refund cases, and Fifth Amendment takings claims.15United States Court of Federal Claims. Frequently Asked Questions
How Federal Sentences Work
The Guidelines
Federal sentences are shaped by the U.S. Sentencing Guidelines, which use a grid plotting the seriousness of the offense (43 levels) against the defendant’s criminal history (six categories). The intersection produces a recommended range of imprisonment.16United States Sentencing Commission. An Overview of the Federal Sentencing Guidelines Since United States v. Booker (2005), the guidelines are advisory. Judges must calculate the range and consider it, but they can sentence above or below it if they explain their reasoning.17United States Sentencing Commission. Report on the Continuing Impact of United States v Booker on Federal Sentencing
Good Conduct Time
The Sentencing Reform Act of 1984 abolished parole for federal crimes, so there is no board that can grant release based on rehabilitation.18United States Courts. Federal Probation – Reflecting on Paroles Abolition in the Federal Sentencing System What remains is good conduct time. Under 18 U.S.C. § 3624(b), inmates who follow institutional rules can earn up to 54 days of credit for each year of the sentence imposed. In practice, a well-behaved prisoner serves about 85 percent of the sentence pronounced in court.19Office of the Law Revision Counsel. 18 USC 3624 – Release of a Prisoner The First Step Act of 2018 expanded that credit and applied the change retroactively.20Federal Register. Good Conduct Time Credit Under the First Step Act
The First Step Act also created a separate category of earned time credits for inmates who complete recidivism-reduction programs or productive activities. These can be applied toward earlier transfer to a halfway house or home confinement.21United States Sentencing Commission. First Step Act Earned Time Credits Not everyone qualifies; inmates facing deportation or assessed as high risk may be excluded.
Mandatory Minimums and the Safety Valve
For some offenses, Congress has removed judicial discretion by setting mandatory minimum sentences. Drug trafficking is the most prominent example: five-year and ten-year minimums are triggered by the substance and quantity involved, and a 20-year minimum applies when the offense causes death or serious injury.22Department of Justice. Frequently Used Federal Drug Statutes
The “safety valve” under 18 U.S.C. § 3553(f) lets judges sentence below the mandatory minimum in drug cases if the defendant has a limited criminal history, used no violence or firearms, held no leadership role, caused no deaths or serious injuries, and truthfully cooperated with the government.23Office of the Law Revision Counsel. 18 USC 3553 – Imposition of a Sentence Prosecutors can also move to reduce a sentence when a defendant provides substantial assistance in other investigations.
Supervised Release
Federal sentences don’t end at the prison gate. Most defendants face a term of supervised release afterward, similar to probation. Maximum terms depend on the severity of the conviction: up to five years for serious felonies, three years for mid-level felonies, and one year for lower-level felonies or misdemeanors.24Office of the Law Revision Counsel. 18 USC 3583 – Inclusion of a Term of Supervised Release After Imprisonment Standard conditions include staying drug-free, submitting to testing, making restitution, and avoiding new criminal conduct. Violations can send someone back to prison.
Being Charged Twice for the Same Act
Because the federal government and each state are treated as separate sovereigns, the same act can be prosecuted as two distinct offenses in two different court systems. Someone whose armed robbery violates both state and federal law can face trial in both without triggering the Fifth Amendment’s protection against double jeopardy. The Supreme Court reaffirmed this in Gamble v. United States (2019), holding that the double jeopardy clause protects against being tried twice by the same sovereign, not by two different ones.25Justia U.S. Supreme Court Center. Gamble v United States, 587 US (2019)
Dual prosecution is uncommon in practice. Federal prosecutors typically step in when they believe a state proceeding won’t produce an adequate outcome, or when the federal interest justifies independent action. When both systems impose sentences, judges can order them to run concurrently or consecutively.
Rights in Federal Criminal Cases
Federal investigations must satisfy the Fourth Amendment’s probable cause requirement before searching a person or property. Under Federal Rule of Criminal Procedure 41, a magistrate judge can issue a search warrant only after receiving a sworn affidavit establishing probable cause to believe that evidence, contraband, or instrumentalities of a crime will be found at the place to be searched.26Legal Information Institute. Rule 41 – Search and Seizure
If you’re charged with a federal felony or serious misdemeanor and can’t afford a lawyer, you have the right to a court-appointed attorney under the Criminal Justice Act. The court must advise every unrepresented defendant of that right and appoint counsel when the defendant is financially unable to hire one and does not waive representation.27Office of the Law Revision Counsel. 18 USC 3006A – Adequate Representation of Defendants Districts with at least 200 appointments per year run a federal public defender office; elsewhere, courts draw from an approved panel of private attorneys.
Federal Taxes: The Everyday Touchpoint
Taxation is where most people meet federal authority firsthand. The IRS administers the Internal Revenue Code and enforces filing requirements. Missing a filing deadline triggers a failure-to-file penalty of 5 percent of the unpaid tax for each month the return is late, capped at 25 percent. Returns more than 60 days overdue face a minimum penalty of the lesser of $525 (for returns due in 2026) or 100 percent of the tax owed.28Internal Revenue Service. Topic No. 653, IRS Notices and Bills, Penalties and Interest Charges These are civil penalties. The IRS also has criminal enforcement authority for willful tax evasion, filing false returns, and related conduct, which is why compliance occupies so much of how individuals and businesses experience the federal system.