Judicial review is the power of federal courts to declare acts of Congress, the executive, and the states unconstitutional and refuse to give them legal effect. The Supreme Court established this power in Marbury v. Madison (1803), reasoning that because "it is emphatically the province and duty of the judicial department to say what the law is," a court confronted with a statute that conflicts with the Constitution must apply the Constitution as the superior law. Here is the thing every 1L needs to sit with: judicial review is not written into the Constitution. Nowhere does the text say "the Supreme Court may strike down laws." It is a judicial construction—and the fact that the entire American constitutional order rests on an inference the Court drew about its own authority is exactly what makes this the first, and most philosophically loaded, doctrine in your Con Law course.

What is judicial review, exactly?

Judicial review is the authority of courts to review the constitutionality of government action—legislative, executive, or state—and to invalidate any action that conflicts with the Constitution. It has two distinct dimensions your professor will keep separate:

• Judicial review of federal action. The power to hold that a federal statute or executive act violates the Constitution. This is the Marbury power.
• Judicial review of state action. The power of the federal courts—and specifically the Supreme Court—to review and reverse state legislation and even state-court judgments that conflict with federal law or the Constitution. This is a separate line of cases and a separate holding.

Do not blur these. A common early-course mistake is to treat Marbury as having settled everything. It settled the Court's power over Congress. It did not establish the Court's supremacy over the states—that took Martin v. Hunter's Lessee and Cohens v. Virginia more than a decade later.

Where does the power of judicial review come from?

The honest answer—and the one that scores points—is that judicial review comes from an argument, not from a clause. Marbury v. Madison (1803) is the source. Chief Justice John Marshall built the power from three moves:

1. The Constitution is supreme, written, and paramount law. The people established a constitution of enumerated and limited powers. If the legislature could pass any law it wished regardless of the Constitution, the written limits would be pointless.
2. A law repugnant to the Constitution is void. If a statute conflicts with the Constitution, the two cannot both govern the same case. One must yield—and the superior, paramount law (the Constitution) prevails over the ordinary law (the statute).
3. Courts must decide which law applies. Because "it is emphatically the province and duty of the judicial department to say what the law is," when a court must decide a case governed by two conflicting rules, it is the court's job to determine which controls. If the Constitution controls, the court must apply it and disregard the conflicting statute.

Marshall also pointed to textual footholds—the Supremacy Clause (Art. VI), the "arising under" language of Article III extending the judicial power to cases arising under the Constitution, and the judicial oath to support the Constitution. But make no mistake: the structural inference is doing the heavy lifting. That is why the doctrine is contestable, and why your professor will press on it.

How Marbury actually reached the question (the part students skip)

The genius of Marbury—and a favorite exam and cold-call angle—is procedural. William Marbury sued for a writ of mandamus to force delivery of his judicial commission, and he filed directly in the Supreme Court under a provision of the Judiciary Act of 1789. Marshall held that (1) Marbury had a right to the commission, and (2) mandamus was an appropriate remedy—but (3) the statute purporting to give the Supreme Court original jurisdiction over the mandamus claim was unconstitutional, because Article III's enumeration of the Court's original jurisdiction cannot be enlarged by Congress. So the Court struck down the very statute that gave it the power to hear the case—and thereby declined to issue the order against the Jefferson administration.

Why this matters for you: Marshall asserted the power of judicial review in the same breath that he declined to exercise power against the executive. He gained the doctrine and lost the case—a politically bulletproof move. If a professor asks "why is Marbury so clever?" this is the answer.

Judicial review over the states: Martin and Cohens

Two follow-on cases complete the doctrine and are frequently tested as a set.

Martin v. Hunter's Lessee (1816) established that the Supreme Court has appellate jurisdiction to review the decisions of state courts on questions of federal law. Virginia argued that as a sovereign, its highest court was not subject to reversal by a federal court. The Supreme Court (Justice Story) rejected this, holding that Article III's judicial power extends to all cases arising under federal law regardless of which court system they originate in, and that uniformity of federal law would be impossible if fifty state courts could each interpret the Constitution finally for themselves.

Cohens v. Virginia (1821) extended this to criminal cases and confirmed that the Court could review a state-court judgment even when the state itself was a party. Marshall again emphasized the need for a single, supreme interpreter of federal law.

Bottom line for your outline: Marbury = review of Congress; Martin and Cohens = review of the states and state courts. Keep the two threads separate on an exam.

The elements/scope of the doctrine

Judicial review is a power, not a test, so it has scope rather than "elements." Frame it this way:

1. The subject of review: federal statutes, federal executive action, state statutes, and state-court judgments—all measured against the federal Constitution (and, for state law, against federal statutes and treaties via the Supremacy Clause).
2. The reviewing courts: all federal courts may exercise judicial review; the Supreme Court is the final arbiter. State courts also apply the Constitution but are subject to Supreme Court review on federal questions.
3. The effect: an unconstitutional act is treated as void—the court refuses to give it legal effect in the case before it. (Whether that operates as a formal "strike" erasing the law or merely a refusal to apply it is a subtle jurisprudential point; for exam purposes, treat the law as unenforceable.)
4. The limits: justiciability. Courts may only exercise this power within a real case or controversy. This is where most exam issues actually live.

The limits on judicial review: justiciability

This is the practical payoff of the doctrine and the part that shows up most on exams as a threshold issue. Because judicial review only operates within Article III's "cases" and "controversies," courts have built doctrines that gate when they will decide constitutional questions:

• No advisory opinions. Rooted in the correspondence between the Jay Court and President Washington, federal courts will not answer hypothetical legal questions outside a concrete dispute.
• Standing. The plaintiff must have a concrete, particularized injury in fact, caused by the defendant, that is redressable by the court (Lujan v. Defenders of Wildlife). No standing, no judicial review.
• Ripeness. The dispute must be sufficiently developed; courts won't decide claims resting on contingent future events.
• Mootness. A live controversy must exist throughout the litigation (with exceptions for wrongs "capable of repetition yet evading review").
• Political question doctrine. Some issues are committed by the Constitution to the political branches or lack judicially manageable standards (Baker v. Carr gives the six factors). Courts decline to review these.

The exam move: before you can even reach whether a law is unconstitutional, you must confirm a court can hear the case. Justiciability is the front door to judicial review.

Worked example

Hypo: Congress passes a statute directing that the Supreme Court, sitting in original jurisdiction, must hear all constitutional challenges to a new federal agency. A litigant files directly in the Supreme Court. What result?

Analysis: This is Marbury redux. Article III fixes the Court's original jurisdiction (cases affecting ambassadors, and those in which a state is a party). Congress cannot enlarge it by statute. The Court would hold the jurisdiction-expanding statute unconstitutional and dismiss for lack of original jurisdiction—exercising judicial review to strike the very law that purported to route the case to it. The point the grader wants: judicial review lets a court invalidate a statute, and Congress cannot statutorily rewrite Article III's jurisdictional grants.

The counter-majoritarian difficulty (the theory hook)

Every serious Con Law course will surface the critique, so have it ready. Judicial review empowers unelected, life-tenured judges to override laws passed by democratically elected majorities. Alexander Bickel called this the "counter-majoritarian difficulty." Defenders (Federalist No. 78, Hamilton) respond that the judiciary is the "least dangerous branch," that it enforces the will of the people as embodied in the Constitution against transient legislative majorities, and that judicial review protects minorities and constitutional limits from majoritarian overreach. If your professor is theory-inclined, being able to state the tension—and both responses—in two clean sentences is worth real exam points and will carry a cold call.

The exam trap

The classic error: writing that the Constitution "grants" the Supreme Court the power of judicial review. It does not. The power is a judicial construction from Marbury built on structural inference plus supporting text. Say "established in Marbury v. Madison," not "provided by Article III." A second trap: conflating judicial review of Congress (Marbury) with review of the states (Martin/Cohens)—cite the right case for the right power. A third: skipping justiciability. If a fact pattern raises standing or a political question, the graceful answer addresses whether the court can review at all before analyzing the merits. Many students dive straight to "the law is unconstitutional" and lose the threshold points.

Related doctrines and how they interact

• Supremacy Clause (Art. VI): supplies the textual basis for the Constitution's superiority and for reviewing state law—the engine behind Martin and Cohens.
• Justiciability (standing, ripeness, mootness, political question): the limits on when judicial review may be exercised. Treat them as the gate around the power.
• Congressional control of jurisdiction (Exceptions Clause, Art. III): Congress can regulate the Court's appellate jurisdiction, raising the question of whether it can strip the courts of the power to hear certain constitutional claims—a live limit on judicial review's reach.
• Separation of powers: judicial review is one branch checking the others; every SOP case assumes the Court's authority to referee, which is itself a product of Marbury.

Understand judicial review and you understand why the rest of the course is even possible: it is the doctrine that gives every later case its bite. Get it cold now and the whole semester gets easier.