The need for our government was outlined in the second sentence of the second paragraph of the Declaration of Independence:
"That to secure these rights, governments are instituted among men, deriving their just powers from the consent of the governed, that whenever any form of government becomes destructive of these ends, it is the right of the people to alter or to abolish it, and to institute new government, laying its foundation on such principles and organizing its powers in such form, as to them shall seem most likely to effect their Safety and Happiness."
The first sentence of the U.S.Constitution, the preamble, says what the purpose of our government is:
"We the People of the United States, in order to form a more perfect union, establish justice, insure domestic tranquility, provide for the common defense, promote the general welfare, and secure the blessings of liberty to ourselves and our posterity, do ordain and establish this Constitution for the United States of America."
To me, this is why we have a government and what we expect from the government. Nothing more, nothing less.
Wise words from a bunch of evil slave owners, huh?