Why is there sometimes conflict and tension between police, prosecutors, and corrections? Why is there often tension and conflict between state, federal, and local authorities? What can be done to ease or lessen this tension and conflict?

Conflict between states and the federal government almost always revert back to interpretations of the Tenth Amendment of the Constitution: "The powers not delegated to the United States by the Constitution, nor prohibited by it to the States, are reserved to the States respectively, or to the people."

The only thing that can change that would be a more specific Constitution or a limitation on the court's ability to change it.

Inter-agency conflicts are the result of poor management from the executive branch that oversees their operation. Branches that are allowed to function on their own generate more friction than those that operate as a working part of a well managed justice system.