When two laws conflict with each other, the one higher in the legal hierarchy wins: the U.S. Constitution sits at the top, federal statutes and treaties come next, then state constitutions and statutes, then local ordinances. When the two laws sit at the same level, courts apply interpretive rules — the more specific law controls over the more general, and a newer law controls over an older one — and they strike down a statute only when no reading can make both work.
Federal Law Beats State Law
The anchor for the whole system is Article VI of the Constitution, the Supremacy Clause. It declares the Constitution, federal statutes, and treaties “the supreme Law of the Land” and binds state judges to them regardless of what a state’s own constitution or laws say.1Library of Congress. Article VI – Clause 2 When federal and state law genuinely conflict, federal law wins.
Marijuana is the clearest live example. Many states have legalized recreational or medical use, but federal law still classifies marijuana as a Schedule I controlled substance under the Controlled Substances Act.2United States Drug Enforcement Administration. Drug Scheduling As of early 2026, a rescheduling process is underway following a December 2025 executive order directing the Attorney General to move marijuana to Schedule III, but no final action has been taken.3Congress.gov. Legal Consequences of Rescheduling Marijuana The federal government has largely declined to prosecute people complying with state law, but that is enforcement discretion, not legal reconciliation. The conflict is dormant, not resolved.
What Counts as a Conflict: Preemption
A state law doesn’t automatically fall just because federal law touches the same subject. Courts ask whether federal law actually preempts it, and they recognize three ways that happens.4Congress.gov. Federal Preemption – A Legal Primer
- Express preemption, where Congress writes directly into a statute that federal law displaces state law on a particular subject. The text says so.
- Field preemption, where federal regulation of an area is so dense that courts conclude Congress meant to occupy the whole field. Immigration and nuclear safety are typical examples.
- Conflict preemption, where it is physically impossible to comply with both laws at once, or the state law stands as an obstacle to what Congress was trying to achieve.
A state law that merely adds to federal requirements, without contradicting them, can survive. A stricter state pollution limit, for instance, may stand if Congress set its own rule as a floor rather than a ceiling. The question courts work through is whether Congress intended to let states go further or to shut that door.4Congress.gov. Federal Preemption – A Legal Primer
State Law Beats Local Ordinances
The same logic repeats one level down. Cities and counties derive their power from the state, so state law overrides local ordinances in a conflict. A state legislature can expressly bar local governments from regulating a subject, or a court can find the state’s regulation thorough enough to displace local rules by implication.
How much latitude a city has depends on whether the state follows “home rule” or a more restrictive model. Under the restrictive approach, a locality can only exercise powers the state has expressly granted, and ambiguity gets resolved against the locality. Home rule flips that presumption: local governments have broad authority unless the state clearly takes it away. Even then, the state legislature can preempt local law when it speaks with sufficient clarity.
Executive Orders Cannot Override Statutes
A president can direct federal agencies on how to carry out existing laws, but an executive order cannot override a federal statute. The Supreme Court drew that line in Youngstown Sheet & Tube Co. v. Sawyer (1952), striking down President Truman’s order seizing steel mills during the Korean War. The Court held that the president was trying to exercise lawmaking power that belongs to Congress.5Justia Law. Youngstown Sheet and Tube Co v Sawyer, 343 US 579 (1952) Presidential power is strongest when Congress has authorized the action and weakest when Congress has prohibited it. An executive order that collides with a statute falls into that weakest category and will not survive a legal challenge.
When Two Laws Sit at the Same Level
Hierarchy only answers the question when the two laws come from different levels. If two federal statutes clash, or two statutes within the same state, courts turn to interpretive principles.
The Specific Beats the General
If one law addresses a subject broadly and another tackles a narrower slice of the same subject with more detail, the specific law controls within its domain. Picture a general statute setting a 65 mph highway speed limit and a separate statute setting 55 mph for commercial trucks. A court would read the truck statute as a deliberate exception, not a drafting error. When a legislature writes a targeted law, that focused attention signals a policy choice, and courts presume the broader law was not meant to silently undo it.
The Newer Beats the Older
When two laws at the same level are genuinely irreconcilable, the one enacted more recently prevails. If a legislature passed a new law knowing the old one existed and the two cannot coexist, the newer law reflects current intent. This only kicks in when the conflict is real; courts will not use a new law to wipe out an older one if any reasonable reading lets both stand.
Conflicts Between Two States’ Laws
Not every conflict runs up and down the hierarchy. If you live in one state and work in another, get hurt in a state you’re visiting, or sign a contract across state lines, you can land between two sets of rules.
The Constitution’s Full Faith and Credit Clause requires each state to respect the judicial proceedings and public records of every other state, which is why a divorce granted in one state must be recognized in all of them.6Library of Congress. Article IV Section 1 But that clause does not decide which state’s law governs a dispute in the first place.
For that, courts use choice-of-law analysis. Approaches vary, but the most common modern method asks which state has the most significant relationship to the dispute. Judges weigh where the events happened, where the parties live, which state’s policies are most directly affected, and what the parties reasonably expected. In contracts, the parties can often head off the uncertainty by naming a governing state in the agreement itself, and courts generally honor that choice.
Agency Regulations After Loper Bright
Federal agencies write detailed regulations to carry out the laws Congress passes. For forty years, when an agency’s reading of an ambiguous statute conflicted with a court’s reading, judges usually sided with the agency under a doctrine called Chevron deference.
That changed in June 2024. In Loper Bright Enterprises v. Raimondo, the Supreme Court held that the Administrative Procedure Act requires judges to exercise their own independent judgment on questions of law. Agencies can still offer their views and courts can find that input helpful, but automatic deference is gone. Prior decisions made under Chevron are not automatically overturned, but new disputes face stricter judicial review.7Supreme Court of the United States. Loper Bright Enterprises v Raimondo, 603 US (2024) If you are trying to follow a regulation that seems to stretch beyond the underlying statute, courts are now more willing to second-guess the agency.
Dual Sovereignty in Criminal Cases
Overlapping federal and state authority produces a result many people find surprising. If a single act violates both federal and state law, both governments can prosecute, and an acquittal in one system does not block prosecution in the other. This is not a loophole in the Fifth Amendment’s double jeopardy protection; it is how the amendment has been read since the 1920s.8Library of Congress. Amdt5.3.3 Dual Sovereignty Doctrine
The reasoning is that the federal government and each state government are separate sovereigns, each with independent authority to define and punish crimes. One act can offend two legal systems and constitute two offenses. The Supreme Court reaffirmed this in 2019 in Gamble v. United States, rejecting the argument that applying the Double Jeopardy Clause to the states through the Fourteenth Amendment should collapse the distinction.9Justia Law. Gamble v United States, 587 US 678 (2019) Two different states can likewise prosecute a person for conduct that crossed their borders. The limit: two bodies answering to the same sovereign cannot both prosecute, so a municipal conviction bars the parent state from charging the same offense again.
How Courts Actually Resolve the Conflict
Judges do not rush to strike down laws. Their first move is to harmonize — to read each law in a way that avoids the conflict, often by concluding the two apply to different situations or different groups.10United States Courts of Appeals for the Armed Forces. Miscellaneous Matters – Statutes, Treaties, Regulations, Executive Orders, Directives – Generally Courts assume the legislature did not intend to contradict itself and look for an interpretation that gives both statutes work to do. Only when the conflict cannot be avoided will a court declare one law invalid or superseded.
Severability
When a court strikes down part of a law, the next question is whether the rest survives. Many statutes include severability clauses saying the remaining provisions stay in effect if any one is found invalid. Courts treat those clauses as a strong signal from the legislature but not an absolute command. A judge will still ask whether the surviving provisions can function on their own and whether the legislature would have passed them without the invalid piece. If cutting out the unconstitutional part guts the statute’s purpose, the whole law may fall.
Getting an Answer Before You Act
If you are caught between two conflicting legal obligations, you do not have to guess which to follow and hope you chose right. Federal courts and most state courts can issue declaratory judgments, which are binding rulings that define the parties’ legal rights and obligations without ordering anyone to do anything or awarding damages.11Office of the Law Revision Counsel. 28 USC 2201 – Creation of Remedy You need an actual, concrete dispute — courts will not answer hypothetical questions — but you do not have to wait until you have been sued or charged. A declaratory judgment lets you get an authoritative answer before you act, rather than after you have already violated one of the laws.