Whereas judicial decisions are more likely to concern substantive matters of law and definitions of legal concepts, legislative adjustments generally reflect social consensus, particularly over large spans of time. Admittedly, political access and the relative ability of specific individuals, communities, and entities to generate legislative changes beneficial to them are not, in any sense, equal when viewed from the microcosmic perspective. Nevertheless, over time, changes in the American criminal justice are largely functions of widely-shared societal concerns and social values in the United States. In recent years, the American criminal justice system has changed in several significant respects: it has become increasingly federalized; it seen a dramatic increase in the privatization of criminal justice facilities; and it has become ever-more effective by virtue of its technological...

Likewise, concepts and principles of criminal reform have continually undergone cyclical changes, due in part to unanticipated flaws in prior approaches or simply to changes in society and/or the nature of certain criminal activities and tendencies in society at particular times.
In the modern era of American history with round-the-clock access to information and instantaneous electronic communication, social influences and trends in public opinion probably play more of a direct role in shaping elements of the criminal justice system than in previous eras. Ultimately, the American criminal justice system will always continue to change and to evolve in ways necessary for it to uphold the values and to achieve the goals of criminal justice as they are determined by American citizens through their opinions and concerns expressed by their formal government representatives.