The compact, or constitutional covenant, is an open or public agreement between members who share a common bond and enjoy equal status. While the terms "compact," "covenant," and "public contract" can be used interchangeably, the compact is different from the textual constitution or charter. The idea of the compact as applied to government in the United States is generally associated with John Locke, an eighteenth-century English philosopher who based his theory of government on a compact. The nature of the compact can vary depending upon who the parties to the agreement are and what is created by the agreement. The compact makes an essential contribution to American constitutionalism whether it is a product of the states or the people, or whether it creates a social or a political system. The constitutional compact is fundamental. It is often referred as the basic law, the organic law, the supreme law of the land, or the higher law.