[Introduction to Constitutional Law #8] Do fundamental human rights apply between private citizens? (General Theory of Human Rights and Horizontal Effect)

The reason for the concept of "horizontal effect"

Do you know what the basic principles of the Constitution are? There are several, but one of them is the limitation of state power. (For details, please see Introduction to Constitutional Law #1, which I highly recommend reading.)

Now, with an understanding of this constitutional philosophy, I have a question for you. Do you think the contents of the Constitution (mainly fundamental human rights) can be applied between fellow Japanese citizens? We will answer this question in this article. This is what is known as the "horizontal effect."

Main theories

Here, I will introduce the representative theories.

Direct Application Theory

The Direct Application Theory is a theory (way of thinking) that attempts to directly apply human rights provisions, which are intended to protect citizens from state power, to private individuals such as between companies and citizens, or between citizens themselves.

Today, there are many powerful corporations, and even between private individuals, the power balance between a single citizen and a corporation tends to tilt toward the corporation. Even between citizens, differences in status and other factors inevitably create disparities in power. In such a society, there is a need to protect human rights not only against state power but also between private individuals. The strength of the Direct Application Theory is that it can achieve this.

However, this Direct Application Theory is not widely supported or adopted in practice (mainly in judicial precedents). One reason for this is the existence of the "principle of private autonomy." The principle of private autonomy is the principle that citizens can freely decide the contents of contracts and rules among themselves. The Direct Application Theory could potentially interfere with this principle of private autonomy.

Indirect Application Theory

If the Direct Application Theory is not adopted for the reasons mentioned above, does the horizontal effect not exist? Actually, that is not the case. The Indirect Application Theory is what is widely adopted in current judicial precedents. The Indirect Application Theory does not directly apply the human rights provisions of the Constitution of Japan to private individuals. Instead, it applies them indirectly through the interpretation of private law provisions such as the Civil Code.

Main judicial precedents

There are various judicial precedents regarding the horizontal effect, but here I will introduce two representative cases.

1. Mitsubishi Plastics Case

This is a Supreme Court precedent that disputed whether a company could refuse to hire a student based on their ideology. When it was discovered during the probationary period at Mitsubishi Plastics, Inc. that the student had participated in student movements in the past, the company decided not to hire the student, leading the student to file a civil lawsuit. The issue was whether the freedom of thought and conscience guaranteed by the Constitution applies to relations between private individuals (against a company).

2. Showa Women's University Case

This is a case where a student attending Showa Women's University was expelled by the university for participating in student movements. The student filed a civil lawsuit against the university. Here, too, the issue was whether the freedom of thought and conscience applies to relations between private individuals (against a university).

These precedents are explained in detail in the following articles, so please take a look if you are interested.

Summary of this article

• Constitutional provisions are, in principle, applied against the state.

• Between private individuals, they are applied indirectly through laws such as the Civil Code.

• This is called the theory of indirect application.

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Related Articles

A list of other introductory articles on the Constitution can be found here.