Lord Bingham, a former Senior Law Lord, wrote a popular level book The Rule of Law wherein he discussed some features associated with it, including that of "Equality before the Law". However, right from the subheading the concept becomes problematic. He writes:
The laws of the land should apply equally to all, save to the extent that objective differences justify differentiation.
The first question which we would naturally ask would be: But what constitute "objective differences" which "justify differentiation"? The incredible thing about his book is that he betrays absolutely no consciousness of the difficulties of determining what exactly constitutes this. He gives some examples where "we would also accept that some categories of people should be treated differently because their position is in some important respect different", e.g. children, prisoners, the mentally ill. But otherwise, he simply reiterates the same principle without explaining *how* or *why* those are relevantly or importantly different:
None of these examples (which could of course be multiplied) is problematical, so long as the law treats people differently because their positions are, genuinely, different. But any departure from the general rule of equal treatment should be scrutinized to ensure that the differential treatment is based on real differences.
Again, the burning question is obviously: what constitutes "real differences"? What constitutes "genuinely" different? The problem isn't that he fails to provide a satisfactory solution, or that his solution is bad. The incredible problem is that he betrays absolutely no consciousness at all that this is a problem. He treats the concept as if it were obvious and that it is clear how to apply the concept, and doesn't even bother mentioning *any* difficulties at all with the concept.
This blindness becomes obviously problematic when he attempts to discuss another example concerning the difference between citizens and non-citizens:
It would be comforting to treat principle [of equality before the law] as of antiquarian interest only. But this would be unrealistic, as the treatment of non-nationals in Britain and elsewhere reveals. As already pointed out, the position of a non-national with no right of abode in Britain differs from that of a national with a right of abode in the obvious and important respect that the one is subject to removal and the other is not. That is the crucial distinction, and differentiation relevant to it is unobjectionable and indeed inevitable. But it does not warrant differentiation irrelevant to that distinction, as Lord Scarman made clear in a House of Lords case in 1983:
"Habeas corpus protection is often expressed as limited to ‘British subjects’. Is it really limited to British nationals? Suffice it to say that the case law has given an emphatic ‘no’ to the question. Every person within the jurisdiction enjoys the equal protection of our laws. There is no distinction between British nationals and others. He who is subject to English law is entitled to its protection. This principle has been in the law at least since Lord Mansfield freed ‘the black’ in Sommersett’s Case (1772) 20 St T 1.12"
The message seems clear enough. But it did not deter Parliament from providing, in Part 4 of the Anti-terrorism, Crime and Security Act 2001, for the indefinite detention without charge or trial of non-nationals suspected of international terrorism, while exempting from that liability British nationals who were judged qualitatively to present the same risk at the time.
He simply assumes as his premise that suspects of international terrorism are not relevant differences from the rule that everyone should be afforded Habeas corpus protection, he doesn't try to argue for it. But whether or not being suspected of international terrorism is a relevant difference is by no means self-evident, it may or may not be, but it has to be litigated and argued for, it cannot simply be assumed as a premise which is obvious and self-evident. He doesn't even just mention that there might be disagreements on whether this is a relevant difference, he just assumes that it is uncontroversial that it is not.
But there is perhaps a reason why the good Law Lord is deliberately so blind to this blackhole in his theory: if he concedes that what constitutes objective and relevant differences is an ambiguous matter, or a matter of *political* value judgement, then it cannot be a legal matter anymore. It will be a matter of political choice, of which he, as a judge, is in no position to determine. However if judges are not a position to determine what constitutes relevant, important, or objective differences as to justify unequal treatment, then it ceases to be a legal concept which judges can apply by themselves. The categories of differences will have to be carved out by political will and other political institutions of which the courts have no special competence to determine. In other words, ironically, the concept of equality under the law is worthless as a legal concept.
The only way to make it meaningful would be to modify the good Law Lord definition to: "Everyone should be treated equally according to the categories of the law". Thus, if a category is undefined in the law, it has no legal relevance. But while this does provide meaningful guidance to judges, it will eviscerate most of their power. If the law carves out racial, religious, or sexual categories for different treatment, the courts must apply the categories as carved out by the law and cannot annul those categories as irrelevant or unimportant differences. The law as such can discriminate at will and judges can only apply those discriminatory categories. The most they can do, on this redefinition, is to refuse to acknowledge differences which the law does not define.
It seems utterly bizarre to me that a Senior Law Lord should betray absolutely no consciousness of the problematic nature of what constitutes relevant or important differences. But then again, I suppose that's the nature of the English in general: they treat their value concepts as obvious and self-evident, welling up from their visceral reactions, and simply lack the mental capacity to interrogate them.