Which phrase reflects the idea of self-government in the Constitution?

The phrase "We the People" encapsulates the concept of self-government as it emphasizes the authority and sovereignty of the populace. This opening line of the preamble to the Constitution signifies that the government derives its power from the consent of the governed. It reflects the idea that the people are the ultimate source of political power and that they have the right to govern themselves. This foundational principle underpins the democratic structure of the United States and highlights the importance of participation and representation in government.

In contrast, the other phrases, while significant in their own rights, do not directly convey the concept of self-government as effectively. "Life, Liberty, and Pursuit of Happiness" speaks to individual rights and freedoms but does not explicitly address the source of government authority. "To form a more perfect Union" suggests an aim for improvement in governance but lacks the explicit notion of the people's role in government. The phrase "We hold these truths to be self-evident" establishes the philosophical foundation for rights but does not specifically denote self-governance. Thus, "We the People" stands out as the most direct reflection of the self-governing principle enshrined in the Constitution.