The people are the source of all power when they vote for people to represent their interest.
The principle of popular sovereignty is expressed in the opening phrase of the preamble "we the people." It is also found in various articles and sections,including the following:The House of Representatives shall be composed of Members every second Year by the People of several States。 一Article I,Section 2,Clause I
There are rules for goverment and laws that help keep order. When we have a question about how to govern we use the rules set up in the constitution to guide us. Everyone no matter who they are must fallow the same rules and laws.
EX:The Citizens of each State shall be entitled to all Privileges and Immunities of Citizens in several States. -Article IV,Section 2,Clause 1
There are three separate branches of goverment legislative, executive, and judicial. No one branch can do anything without the other two branches being involved.