So far, as we have discussed, in criminal law the American common law project has fallen into discord. There are three major sets of laws in the United States: the model penal code common law, the traditional American common law, and federal criminal laws. Even among these major streams of there are further variances as courts not subject to superior review decide differently on the same issue or legislatures adopt different laws in relation to the same issue. In other words, in the United States, the common law project has failed.
Except in one area.
The one true area of American common law is constitutional interpretation. In fact, ConLaw is common law triumphant. Of course, whenever you say this people go apoplectic. They'll all splutter something about Constitutional Law being unique and different. It's not a rational reaction; it's simply the response of people who have been taught to think of the Constitution as incomparable holy writ rather than an act. Of course, they are wrong.
As previously discussed, the British common law had no problem incorporating acts into common law. One sovereign meant that as soon as an act was made law it, by definition, became the common law. In the United States many do not understand this as part of the common law because in our separate sovereigns system there were 51 sovereign legislatures passing laws which, by definition, could not become the common law of the land. Thus, American jurists are programmed to overlook the one sovereign act which is common to the entire nation: the United States Constitution.
The Constitution by its very definition is common to us all. As well, case law under it develops exactly as common law is supposed to. Issues are addressed by lower courts either in the federal circuits or the State appellate courts and if there is a major disagreement as to how a particular constitutional provision is to be applied there is a single authority, the United States Supreme Court, which can provide a final answer. There is also a process wherein the body of constitutional law can be changed legislatively by the sovereign, overruling even the Supreme Court, although recourse to this is exceedingly rare because it is extremely difficult (Amendment). In any event, the presence of a single authority ruling on a singular set of laws applicable to the entire nation makes constitutional common law triumphant.
However, as in all common law, the fact that there is a final authority does not make decisions made by that authority well reasoned or even correct. It just makes them final. A perfect example of this in recent times has been the US Supreme Court's jurisprudence as to dog sniffs. The Caballes decision declares that when a dog sniffs at an object and reveals something inside that object no search has occurred. It is an incredibly flawed decision. Nevertheless, by virtue of being decided by the final authority, it is the common law of the entire land.
It is also clear that constitutional common law decisions do not have to reflect a majority position. Constitutional common law decisions have overridden the laws of a significant number of States or a majority. Most recently, this has been seen in the US Supreme Court's hostility to punishment for minors expressed in its rejection of the death penalty for those under 18 years of age (overriding the laws of 25 States) and its rejection of mandatory life sentences for those under 18 who commit certain murders (overriding 28 States and Congress).
Constitutional common law merely provides finality; often it is a choice between two possibilities neither of which is necessarily correct. For instance, in a trial post Miranda the prosecution is not allowed to mention the fact that a defendant refused to talk to the officer about the case. As more recent Supreme Court opinions have reminded us, the purpose of the 5th Amendment is to prevent coerced confessions. Theoretically, it keeps officers from beating confessions out of people (whether they are guilty or not) by making any coerced confession inadmissible. All-in-all, a good idea. However, there's nothing particular to stopping forced confessions that would require that a defendant's voluntary silence should not be commented on in trial. If a defense is offered first at trial and the defendant would have known about it when the officers tried to question him, but he invoked his right to remain silent and the officer stopped questioning him, how would allowing the prosecution to comment on the refusal tend to encourage officers to coerce a confession out of defendants?
All of the above are exemplars of American common laws brought about under the auspices of the United States Constitution (4th, 5th & 8th Amendments). Thus, while the common law seem irretrievably broken in many micro-aspects because of the separate sovereigns, in a macro-aspect it provides an overarching common law framework which has become more and more restrictive as time has passed.