A more thorough explanation:

Substantive due process is a principle that protects fundamental rights from government interference. The Fifth and Fourteenth Amendments of the US Constitution prohibit the government from taking away a person's "life, liberty, or property without due process of law." This means that the government cannot interfere with certain rights that are considered fundamental.

For example, the right to privacy is a fundamental right protected by substantive due process. In the case of Griswold v. Connecticut, the Supreme Court ruled that the government could not prohibit the use of contraceptives by married couples. This decision was based on the right to privacy, which is not explicitly stated in the Constitution but is considered a fundamental right.

Another example of a fundamental right protected by substantive due process is the right to marry. In the case of Loving v. Virginia, the Supreme Court ruled that the government could not prohibit interracial marriage. This decision was based on the principle of substantive due process, which protects the fundamental right to marry.

Overall, substantive due process is a principle that protects certain fundamental rights from government interference. These rights are not explicitly stated in the Constitution but are considered deeply rooted in US history and tradition. Examples of these rights include the right to privacy, the right to marry, and the right to free speech.