Janez is a former constitutional court judge and president of the Constitutional Court of the Republic of Slovenia. Before that he was adviser to the Government of the Republic of Slovenia in relation to environmental protection and public services for environmental protection. He is professor of administrative law and constitutional justice. His narrower field of activity is oriented towards constitutional and administrative law aspects of environmental procedures, public procurement procedures, the protection of free economic initiative and competition, tax procedures and public services. He is an established expert in the constitutional protection of rights of legal entities and individuals. His scientific contributions and expert papers from the said fields are cited in the rulings of the Constitutional Court, and at the invitation of the Constitutional Court he collaborated in constitutional legislation review procedures as an expert for constitutional law issues.