The legal system of the Kingdom of Thailand is based on the civil law legal system. In addition, it is strongly influenced by common law principles. Primary sources of law include the Thai constitution, which is the supreme law, legislation such as codes and acts, decrees and customary principles. Under the current legal system, judicial decisions are not binding; in practice, however, decisions of the Supreme Court are persuasive, have some precedential value and are often used as a guideline for interpretation of  the law.