What Is Social Contract Theory

What is the “social contract theory” and how does this theory affect the ethical conduct of a business within the society in which that business operates? Does the United States follow the social contract theory?
What are the advantages and the disadvantages for a business that decides to be “proactive” in the area of ethics? What are the advantages for a business that decides to be “reactive” in this area? Based on your response, which option would better serve a business? Explain your reasoning.