Introduction: Not Every Law Is a Valid Law
In the United States, there is a hierarchy of law. At the very top sits the U.S. Constitution the supreme law of the land. Every other law federal statutes, state laws, local ordinances, administrative regulations must be consistent with the Constitution. When it is not, the law is unconstitutional and therefore legally void.
This principle known as constitutional supremacy is foundational to the American legal system. And the mechanism by which it is enforced judicial review was established by the Supreme Court in Marbury v. Madison (1803) and has been a cornerstone of American law ever since.
But what exactly makes a law unconstitutional? The answer involves a rich body of constitutional doctrine, judicial standards, and legal principles that every American should understand. At PCFJE, we believe that knowing what makes a law invalid is essential knowledge for every citizen who cares about constitutional governance.
Reason 1: Exceeding Constitutional Authority (Ultra Vires)
A law is unconstitutional if the governing body that enacted it lacked the constitutional authority to do so.
Federal Laws
The federal government has only the powers enumerated in the Constitution primarily in Article I, Section 8. If Congress passes a law that is not connected to any enumerated power, it is unconstitutional.
The most important limits come from:
- Commerce Clause (power to regulate interstate commerce broad, but not unlimited)
- Spending Clause (power to spend for the general welfare but cannot coerce states)
- Necessary and Proper Clause (allows laws “necessary and proper” to carry out enumerated powers but not a blank check)
Example: In United States v. Lopez (1995), the Supreme Court struck down a federal law banning guns near schools because it had no sufficient connection to interstate commerce.
State Laws
States have broader (“police”) powers the general authority to regulate for the health, safety, welfare, and morals of their citizens. But state laws still cannot:
- Violate the federal Constitution
- Conflict with valid federal law (Supremacy Clause)
- Violate state constitutions
Reason 2: Violating the Bill of Rights
Any law federal or state (through the 14th Amendment’s incorporation doctrine) that violates a specific protection in the Bill of Rights is unconstitutional.
First Amendment Violations
A law is unconstitutional under the First Amendment if it:
- Restricts speech based on its content or viewpoint without compelling justification
- Establishes a government religion or substantially burdens religious exercise
- Restricts peaceful assembly or the right to petition
Doctrines to know:
- Prior restraint: Government prohibiting speech before it occurs is presumptively unconstitutional
- Overbreadth: A law is overbroad if it restricts substantially more speech than constitutionally necessary
- Vagueness: A law is void for vagueness if it does not give fair notice of what it prohibits
Fourth Amendment Violations
Laws or government actions that authorize warrantless searches without recognized exceptions, or that authorize seizures without probable cause, violate the Fourth Amendment.
Fifth and Fourteenth Amendment Due Process Violations
Laws that:
- Deprive persons of life, liberty, or property without fair procedures (procedural due process)
- Violate fundamental rights even with perfect procedures (substantive due process)
Eighth Amendment Violations
Laws that impose punishments grossly disproportionate to the offense, or that authorize torture or inhumane treatment, violate the Eighth Amendment.
Reason 3: Violating Equal Protection
A law is unconstitutional under the Equal Protection Clause of the 14th Amendment if it treats similarly situated people differently based on protected characteristics without adequate justification.
The level of judicial scrutiny depends on the classification:
| Classification | Scrutiny Level | Government Must Show |
| Race, national origin | Strict | Compelling interest, narrowly tailored |
| Sex | Intermediate | Important interest, substantially related |
| All other classifications | Rational basis | Legitimate interest, rationally related |
Example: A law that provides benefits to white citizens but denies them to Black citizens would face strict scrutiny and almost certainly be struck down as unconstitutional.
Reason 4: Violating the Separation of Powers
Laws that upset the constitutional balance among the three branches of government are unconstitutional.
Congress Cannot Delegate Core Legislative Power
The non-delegation doctrine holds that Congress cannot hand its fundamental lawmaking power to executive agencies without providing adequate standards to guide their exercise of that power.
Executive Cannot Exercise Legislative Power
When the President or executive agencies create binding law without congressional authorization, they may violate the separation of powers.
Courts Cannot Be Given Non-Judicial Functions
Congress cannot assign functions to courts that are fundamentally legislative or executive in nature.
Example: In INS v. Chadha (1983), the Supreme Court struck down the “legislative veto” a mechanism allowing one house of Congress to invalidate executive action as unconstitutional because it bypassed the constitutional requirement that legislation be presented to the President for signature or veto.
Reason 5: Violating Federalism Principles
Laws may be unconstitutional for violating the constitutional relationship between the federal government and the states.
The Tenth Amendment
Powers not delegated to the federal government are reserved to the states or the people. Laws that commandeer state resources or officials to implement federal programs violate this principle (New York v. United States, 1992; Printz v. United States, 1997).
The Supremacy Clause
State laws that directly conflict with valid federal law are preempted and unconstitutional. However, the federal government must have proper authority for the federal law to be “valid.”
The Dormant Commerce Clause
State laws that discriminate against interstate commerce or impose unreasonable burdens on it can be struck down under the “dormant” or “negative” Commerce Clause doctrine.
Reason 6: Vagueness and Overbreadth
Even a law targeting legitimate government interests can be unconstitutional if it is:
Void for Vagueness
A law is unconstitutionally vague if it does not give persons of ordinary intelligence a reasonable opportunity to understand what it prohibits. Vague laws violate due process by failing to provide fair notice and by giving law enforcement excessive discretion.
Unconstitutionally Overbroad
A law is overbroad if, in attempting to regulate unprotected conduct, it also prohibits or chills a substantial amount of protected constitutional activity. Overbreadth challenges are particularly common in First Amendment contexts.
Reason 7: Bills of Attainder and Ex Post Facto Laws
The Constitution explicitly prohibits:
Bills of Attainder: Laws that impose punishment on specific individuals or groups without a judicial trial (Article I, Sections 9 and 10).
Ex Post Facto Laws: Laws that criminalize conduct that was legal when it occurred, or that increase punishment for past conduct (Article I, Sections 9 and 10).
These prohibitions are among the most explicit anti-tyranny provisions in the Constitution.
How Courts Decide: The Process of Judicial Review
When a law is challenged as unconstitutional, courts follow a structured review process:
- Does the challenger have standing? (concrete injury, causation, redressability)
- Is the case ripe and not moot? (timing considerations)
- What is the appropriate level of scrutiny? (strict, intermediate, rational basis)
- Does the law survive that scrutiny? (does it serve the required government interest in the required manner?)
- What remedy is appropriate? (strike down the entire law, or “sever” unconstitutional provisions while leaving the rest in effect)
The Role of Citizens in Identifying Unconstitutional Laws
Judicial review depends on citizens willing to challenge laws in court. Courts do not proactively review legislation someone must bring a case. This means:
- Citizens must be aware of when their constitutional rights are being violated
- Citizens must have access to legal resources to challenge those violations
- Civil society organizations must support constitutional litigation
- Public education about constitutional rights must be robust and accessible
This is precisely why PCFJE’s educational mission is central to our advocacy work.
Frequently Asked Questions (FAQs)
Q: Who decides if a law is unconstitutional? A: Ultimately, courts decide with the Supreme Court having the final say on questions of federal constitutional law. But the process starts with citizens challenging laws, which is why civic awareness is essential.
Q: Can Congress pass a law that overturns a Supreme Court ruling? A: If the Court struck down a law as unconstitutional, Congress cannot simply re-pass the same law. However, Congress can pass new legislation that complies with the Court’s ruling, or (through Article V) pursue a constitutional amendment that changes the constitutional landscape.
Q: Is a law automatically void once it is declared unconstitutional? A: Yes, in theory. A law declared unconstitutional has no legal force. In practice, agencies and governments must stop enforcing it, though this sometimes requires ongoing court supervision.
Q: Can a state law be constitutional under the federal Constitution but unconstitutional under a state constitution? A: Yes. State constitutions can provide greater protections than the federal Constitution. A state law may comply with federal constitutional minimums while still violating a state constitution’s stronger guarantees.
Q: What is the difference between a law being unconstitutional and a law being unfair? A: A law can be grossly unfair without being unconstitutional. Courts do not strike down laws merely for being bad policy. Unconstitutionality requires a specific violation of a constitutional provision. This distinction is why constitutional reform through Article V is sometimes necessary to create constitutional constraints on laws that are unjust but technically permissible.
Conclusion: The Constitution as a Living Shield
Understanding what makes a law unconstitutional is not just legal knowledge it is civic power. When citizens understand the standards by which laws are judged, they are better equipped to identify violations, support legal challenges, advocate for reform, and hold their government accountable.
No law that violates the Constitution has lasting legitimacy. The history of American constitutional law is a history of courts, citizens, and movements steadily expanding the circle of constitutional protection refusing to accept that unjust laws are permanent.
At PCFJE, we are part of that tradition. We challenge unconstitutional laws. We educate citizens. We build the coalitions that make structural reform possible. And we believe, deeply and without reservation, that a constitutional government is one that follows the Constitution in letter and in spirit.
Know what makes a law invalid. Know your rights. Stand with us.
Join the People’s Convention for Justice and Equality and fight for a truly constitutional America.