Read the preamble to the Constitution. We the People of the United States, in Order to form a more perfect Union, establish Justice, insure domestic Tranquility, provide for the common defence, 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.

In the preamble, the phrase “establish Justice, insure domestic Tranquility” means

to improve the government system and structure.
to create a system of laws for internal peace.
to identify the seat of power in the government.
to install this government system for the nation.