Final answer:
The most important theory in the development of government in the United States is the social contract theory, which states that government derives its authority from the consent of the governed.
Step-by-step explanation:
The most important theory in the development of government in the United States is the social contract theory. This theory, developed by political philosophers such as John Locke and Jean-Jacques Rousseau, posits that government derives its authority from the consent of the governed. According to the social contract theory, individuals willingly give up some of their natural rights and freedoms in exchange for the government's protection of their lives, liberty, and property. The United States Declaration of Independence and the Constitution are both influenced by the ideas of the social contract theory.