So basically, what I want to argue is that principled opportunism (and the Marxist theoretical approach from which it derives), shares some similar presuppositions to natural law jurisprudence, but from these positions comes to a diametrically opposed practical/political standpoint. Hopefully what this can do is help us grasp some of the really interesting things about natural law jurisprudence (especially some of the more recent stuff) and further illuminate what principled opportunism might mean.
To be brief. Natural law jurisprudence tends to approach law as a specific form of social regulation, with its own identity and dynamics. Generally, natural law jurisprudence sees law as a form of regulation in which abstract, formal equality inheres. The next move, is to tie this social form to some kind of form of life. In Finnis, this form of life is one in which individuals are able to pursue diverse life paths (and thus their own ways of engaging in ‘objective goods’); in Simmonds, the form of law grants individuals a certain degree of ‘distance’; no matter how onerous the burden of law’s content, ones dittoes are not dependent on the arbitrary will of a sovereign, since this is always mediated through abstract, prospective rules that treat individuals as formally equal. In sum (and to be somewhat vulgar), these theories link the form of law with a form of life in which abstract individuals are able to pursue their own projects, viz. an idealised form of liberal capitalism (Simmonds in particular is a bit more complicated than this, but my general point is that law is tied to what one might call ‘liberty’).
The next step in this chain of reasoning is particularly interesting. Essentially, once law is tied to a form of life, this form of life is morally evaluated. Both Simmonds and Finnis (and to some degree one can include Fuller, Aquinas, Locke and even Hobbes in this) argue that this form of life is intrinsically morally valuable, inasmuch as it enables individuals to pursue their interests at some degree of distance from other individuals (etc.). In this respect, the form of law itself is intrinsically morally value, given that it is productive of abstract individual liberty. The brilliance of this move comes when it is juxtaposed to the problem of unjust content.
Essentially, given that the form of law is systemically morally good, the moral value of the legal form exists even when it expresses immoral content. For Simmonds this is because there is still a ‘distance’ between the rulers and the rules and for Finnis, this is because the form of law is supportive of a system of individual liberty. This gives rise to what Finnis calls a ‘collateral obligation’ to obey the law. Essentially, when one decides up whether or not to obey the law, the justice or injustice of its content is not the only factor to be taken into account, this has to be weighed against the intrinsic moral value of the legal form (which is produced by/produces an intrinsically moral form of life). Thus, the form of law is valuable, even while the content is variable. It is a case of form asserted against content.
The obvious interesting point from my perspective is the way in which the natural law approach dovetails with that of Pashukanis. Thus, Pashukanis identifies law with a specific form and ties it with a specific form of social life; which – in a less idealised form – is the same of that the natural law jurisprudes, capitalism. However, there is of course a crucial difference in these approaches, which Nigel Simmonds (who has made extensive and fascinating excursions into the Marxist tradition) sums up quite nicely (‘Between Positivism and Idealism’, (1991) 50 Cambridge Law Journal 308 :
The conservative view of law that I am defending has much in common with Marxism. Yet if differs from Marxism in the evaluation that it makes of law.The crucial difference in the Marxist and natural law accounts of the legal form is how they evaluate law and the form of social life it is tied to. Obviously, Marxists are wont to evaluate capitalism of being composed of relations of exploitation and domination, and as a destructive and ultimately (hopefully!) transient phase of human life. I think the crucial move made by Marxists in this respect (and I have elaborated on it more here and here) is that the ‘form’ of capitalism free exchange is structurally tied up with a certain content; it’s not just a case then of the liberal form of capitalism being occasionally confronted with some nasty stuff; but rather that this form systematically throws up problems owing to the realisation of surplus value. Thus, domination, exploitation, class struggles etc. are always produced by the formal equality that characterises capitalism. Chris Arthur puts it rather excellently (in the introduction to the Ink Links Law and Marxism: A General Theory:
From a dialectical point of view a form is the form of its content, and one may be alarmed at the outset if one imagines that Pashukanis proposes to write a treatise on legal forms in abstraction from content. However, this would be a misunderstanding. In characterising law as a bourgeois form he clearly is relating law to a definition material content – the social relations founded on commodity exchange.Thus, on this we can reverse the natural law position. The form of law is not something intrinsically valuable, but (if you’ll allow me) quite the contrary, the form embeds relations of exploitation and domination. And this brings us to principled opportunism, and its complete opposition to the collateral obligation. There, the form of law is invoked against unjust content; thus in spite of its content, the form may compel obedience. But in principled in opportunism the content of law is invoked against the ‘unjust’ (for want of a better word) form, and content may compel obedience (or more likely invocation), in spite of the form. In the collateral obligation, law is in principle valuable, in principled opportunism law is ‘in principle’ not, and as such should never be invoked per se.