Free tool · The Judiciary
Diffuse or Concentrated Constitutional Review? Identify the Model
Constitutional review, the power of courts to test laws against the constitution, is organised in two main ways. In the diffuse (American) model every court can decline to apply an unconstitutional law in the case before it, challenges arise in ordinary litigation and a ruling binds the parties, though precedent spreads its effect. In the concentrated (European, or Kelsenian) model only a specialised constitutional court may rule on constitutionality, ordinary courts refer questions to it, challenges can also come by abstract petitions from officials or by individual constitutional complaints, and a ruling that a law is invalid has effect for everyone. Some systems, such as France with its preventive review, and many others, mix the features.
Tool · Constitutional Review Model Identifier
The diffuse (American) model
- Any court can decline to apply a law that it finds unconstitutional in a case before it (diffuse, or decentralised, review).
- Review takes place after the law is in force (a posteriori).
- Review arises in a concrete case (incidental review): the court is asked about a law that matters to the dispute.
- A ruling binds the parties (inter partes); the law is not formally annulled, though precedent makes the decision effective for others.
Examples: The United States is the classic example; others include Argentina, Australia, Canada (in part) and India (in part).
- The labels are teaching categories. Real systems blend the features, and the dividing lines move as courts and reforms change them.
- The model affects who can bring a challenge, how quickly an unconstitutional law is removed, and how much power ordinary judges have.
Describe how a country reviews laws for constitutionality, who can review, when, how a challenge arises and what a ruling does, and see which model it matches: diffuse (American), concentrated (European), preventive or mixed. The labels are teaching categories and real systems blend features. Runs in your browser; nothing is stored or sent.
How to use it
- Say whether all courts or only a special court can review.
- Say when review happens and how a challenge arises.
- Say whether a ruling binds the parties or everyone.
- Read the model that matches, with examples.
Common questions
What is erga omnes effect?
A ruling that binds everyone and not only the parties. When a constitutional court strikes down a law erga omnes, the law ceases to apply to all.
What is abstract review?
Review of a law in the abstract, without a real case, at the request of officials or institutions.
Do all constitutional courts follow the same model?
No. Systems blend features, and the lines move as reforms change how review works.
Learn the law behind the tool
This tool is part of our The Judiciary course, with lectures, concept maps, flashcards, interactive exercises and a capstone case. The Judiciary: Constitutional Review and Specialized Courts.
More free law tools
General information, simplified, mainly on American law, not legal advice. States and countries differ, and real cases turn on facts that a tool cannot capture.