Final answer:
The term that defines the idea that governments are established to protect natural rights and can be replaced by the people if they fail to do so is A) Social contract. This philosophy, associated with Enlightenment thinkers like John Locke, influenced the drafting of the Declaration of Independence and the general conception of government authority stemming from the consent of the governed.
Step-by-step explanation:
The term that defines the idea that governments exist to protect natural rights and that the people can replace their government if it fails to protect these rights is A) Social contract. This concept was pivotal in shaping the framework of modern democratic societies and influenced revolutionary leaders like Thomas Jefferson when drafting foundational documents such as the Declaration of Independence. According to philosophers like John Locke, governments derive their authority from the consent of the governed, and it is within the people's rights to overthrow a government that does not uphold its end of the social contract.
It is important to understand that the social contract theory is not synonymous with democracy. While democracy involves the direct exercise of power by the people, the social contract can also be used to justify the authority of a monarch who governs in the people's interest. However, as social contract theory evolved, it became more closely associated with the idea of a government that preserves citizens' rights and ensures that they maintain ultimate control over their rulers.