Although you can use your checking account as a reserve account for your cash, much like a savings account, it may not be the best option for that purpose. Most checking accounts do not earn interest, and even those that do typically earn less than a savings account at the same financial institution.
As is the case with other forms of government in American political theory, local governments derive their power from the people; in practice, local governments receive their authorization from their respective states.
Popular sovereignty indicates that the mandate of the people created government, and that political power comes from the people. However, in practice, political leaders abuse their power because they consider themselves sovereigns, instead of public servants.