A quick definition of due process:

Due process is a promise in the Constitution that says the government must follow the law and provide fair procedures before taking away someone's life, liberty, or property. This promise applies to both the federal government and the states. It means that everyone has the right to a fair trial and to be heard before the government takes any action against them. The procedures that are required for due process depend on the situation, but they must always be fair and follow established rules.