Answer:
The purpose of the government according to the Declaration of Independence is to protect people's unalienable or ("natural") rights.
According to the Declaration of Independence, the government gets its power to govern from the people that it governs. As the Declaration says, Governments are instituted among Men, deriving their just powers from the consent of the governed. This was an idea that derived from Enlightenment thinkers such as John Locke.
