Certainly. Whereas, here, I used the contrast merely as a key to open the argument with, it is ultimately widely accepted that most of the world uses one of two systems in the typification of their legal systems, common law and civil law, with a few mixed exceptions, as well as those nations which use sharia, religious law as written by the prophet.
The earlier relates back, though neither should be seen as a direct continuity, to the Code of Justinian¹, and refers to systems built on statutory law, which is to say, law as written, a tradition further reinforced by Kelsen's General Theory of Law and State in 20th century Germany, but which can be found earlier, for instance, in the Napoleonic Code. Kelsen's primary contribution in that regard was the institution of positivist doctrine, laws as written and absolute, but one would do well not to close oneself to different perspectives here.
The later, most well known for its prevalence in the US and the United Kingdom, is built on case law, law by precedent, Unlike civil law, common law was for a long time a system strictly detained to the British Island, however, with the British Empire, most of its subsidiaries would, even after their independence, continue to adopt the system, as is the case with India and the US.
In effect, the key topic to be understood in that regard is that a civil law system seeks to maintain its integrity by the universal application of a same given set of codified laws, whereas previous cases, though they might be used as an argument in the absence of the letter of the law, have no imperative value. On the other hand, common law systems seek to main their integrity not in relying in a single typified code, but rather, by relying on precedent so as to ensure that a given sentence, in a given situation, does not vary from another, therefore maintaining its internal consistency.
That said, let us move on to the matter of bias in a given legal system, and to what extent the point of any given system is a subjective form of justice or another subject altogether. This, being an ardent discussion in the field, rather than a widely accepted classification, I will only loosely approach.
There are two areas widely open to personal influence in any given system, the creation of the laws themselves, which is to say, the legislative body or entity, and the application of these laws, the trial proper, embodied in those magistrates presiding over the sentence, as well as the jury, should the system sponsor trial by such.
In the earlier, we must admit that, even though justice by those common standards of the nation may well be within the legislative body's interests, to say that is their sole interest would be foolhardy at best as an expectation to be assumed upon a fellow human being, And I speak of those common standards of the nation because, ultimately, many aspects of morality are intrinsically cultural, even as the widespreadness of a given set of western values might have led us to believe we've found common human values were there are, in fact, none.
That is not say all of them are, or that I can state objectively which are and which are not. Far from it, if anything, I'd just likewise fall within a cultural standard. That is not to say, however, that tolerance is always the answer; while many of us are taught that from birth as a quintessential value, ultimately, the tolerant who passively stands before the intolerant is just waiting idly for their own destruction or subversion. Here, there is no truth to be found.
That considered, the interests that permeate a given legislative body or entity are manifold; moral values, political interests, personal interests and even mood affect the legislator's decision the same as they would any other individual's, and though certain similarities might remain, not even the moral values are the same for every legislator. Thus, it becomes increasingly difficult to conceive any given legal framework as a work of platonic justice, even judged by the nation's average standards; here, though this is not the start and end of the matter, a convenient simplification would be to say that one such a framework is, first and foremost, a convenient imposition.
Once we move on to the application of that framework, we are forced to add yet another layer of personality, as that system created by a given legislative body or derived from previous trials is once more subjected to interpretation². The presiding magistrate, those parties directly involved, their advocates and, if present, the jury, each have their own established moral framework, when not even personal interests in the trial's outcome, acting as yet another personal filter through which so called justice might be delivered.
Unless law is deemed absolute and perfect as written², and one might then decide to altogether forego trial, these joint particularities will then serve as the final lens through which those original intentions, whichever they be, emanating from the legislative, will be distorted and cast into effect, that is, the sentence itself. More often than not, it is where the outcome agrees with our view that we call it just, and where it disagrees that we call it unjust.
So long as the legal framework does not operate in a fashion thus conflicting so as to alienate large enough a part of the population to jeopardize the present system's legitimacy before the public, so does the framework continue to be considered sufficiently just by the majority and, in tandem, remain legitimate justice. Though there are a few things to be said as to absolute and/or universal values, we would then go from an analysis on the overall framework of legality to a territory deeply ingrained in my own set of beliefs, and so it is for best that we cut this short. I hope it is of some use.
In hindsight, this may well have deviated much too far away from the thread's general intent; please feel free to delete this post if you believe it necessary.
¹consuetudinary law, a tradition most widespread through the Middle Ages, emphasizing local customs, rather than precedent or an unified system as written. Of Germanic tradition, though one should also note it did have a measure of influence in ancient Roman law, customary systems were slowly abandoned as national States formed, for, as they sought to take power from local elites and empower the bureaucracy, and as the scale of administration rose, so were increasingly standardized systems sought and implemented. Nowadays, for reasons all too similar, customary law, where it still exists, detains a subordinate role in the legal hierarchy.
²even civil law systems have this characteristic, codified as they may have become, for written law so clearly stated and weighed thus devoid of external influences that there is no room for argument has not yet been conceived. This is, ultimately, a flaw in Kelsen's predominantly scientific view of Law, in which positive law might consistently adapted in progressive fashion in accordance to the State's desires, rather than being constantly mutated by manifold interests.