Everyone recognizes that the laws governing criminal procedure vary somewhat from state to state. There is often a tendency, however, to underestimate the degree of diversity that exists. Even some of the most experienced practitioners believe that aside from variations on some minor matters, such as the number of peremptory challenges granted, and variation on a few major items, such as the use of the grand jury, the basic legal standards governing most procedures are approximately the same in a large majority of states. I have seen varied evidence of this misconception in practitioner discussions of law reform proposals, particularly at the local level. That misconception ordinarily rests on one or more of the following premises: (1) for those procedures regulated heavily by the federal Constitution, the United States Supreme Court decisions set a uniform standard, except for an occasional state rule that may exceed that standard; (2) for those areas regulated commonly by court rule or legislation, many state provisions are based upon a common model, such as the Federal Rules of Criminal Procedure, and therefore have largely similar standards; (3) for still other areas, common law standards govern, and those standards are fairly uniform. All of these premises contain some truth, yet each overstates the situation. Of the three, the first is the most troublesome - perhaps because it is the most valid - and will therefore be considered at greater length than the others.
Israel, Jerold H. "On Recognizing Variations in State Criminal Procedure." U. Mich. J. L. Reform 15 (1982): 465-96.