A program is a single action or set of actions intended to influence something outside itself. A system is a set of interrelating parts that performs functions inside itself. It is a set of ideas or objects that must work together to perform a particular function. Programs are simple and direct. Politicians like them because they appear to be serious, tough, decisive, and sound-bitable.
Systems are complex and indirect.
For example, under a crime prevention program , crime might be stopped by enforcement agents that intervene directly, at a cost to taxpayers. Under a crime prevention system , crime might be reduced automatically, as a byproduct of another action a system of potential penalties, or perhaps a public education system that provides better opportunities reducing crime because people have less desire to commit it. Similarly, under a forest protection program , deforestation might be stopped by hiring police to arrest violators, or land might be purchased to take it out of the marketplace. Under a forest protecting system , the costs or penalties to the deforester would be generally sufficient to prevent the action, and the land might be of such little value as a source of poorly-harvested timber that no successful business could engage in deforesting practices for long. Both programs and systems are processors of resources.