I read James Allan’s comments on my column in the Australian about the US Supreme Court’s abortion decisions with considerable astonishment – and a fair measure of disappointment. The Spectator’s readers are owed a clarification.

I never suggested that the court should not overturn its previous decisions. Rather, I simply affirmed the position the court has repeatedly stated: that stability in the legal order has a high value; and that as a result, the court should only reverse its prior holdings when not to do so would perpetuate a manifest and harmful error.

That view is hardly mine alone: it is advanced at great length in the abortion decisions themselves; it was put, with considerable force, by the recently appointed justices in their testimony under oath in the Senate; it has been the consensus of Supreme Court jurisprudence since the late 19th century; and it is abundantly reflected in the major scholarly texts. From all of these it emerges, as if with a single voice, that stare decisis is a policy which sets out a rebuttable presumption: that precedent should be allowed to stand unless a highly demanding case can be made for setting it aside.

As best I can tell, Allan believes that placing weight on precedent, and more generally on the policy of stare decisis, is a common law feature which cannot or perhaps should not be transposed to the jurisprudence of a written constitution. The obvious, and obviously fatal, problem with Allan’s claim is that it is starkly inconsistent with the Supreme Court’s own often stated views, as set out, for example, in its 2000 reaffirmation of the Miranda decision.

Additionally, Allan’s claim ignores the widely accepted nature of the American legal order as embodying a constitutionalism of the common law, in which tradition and precedent are regarded as reflecting a collective form of accumulated learning.

It is in that context that leading commentators, such as Harvard Law School’s Richard Fallon and Stanford’s Dan Edelstein, have carefully analysed the crucial role of precedent in Supreme Court decisions, including by contrasting the stare decisis element of American common law constitutionalism with its absence in the constitutional jurisprudence of its French and more broadly, civil law-inspired, counterparts.

Allan’s suggestion that the common law tradition is at odds with American constitutionalism is therefore so plainly incorrect as to be incomprehensible. It is also, it must be said, at odds with the weight of conservative thought, which has always emphasised the desirability of prudence, stability and certainty in legal decision-making.

Given the role of stare decisis as a rebuttable presumption, the only relevant question is whether the court met its own, stringent test in overturning Roe v. Wade. What counts in that respect is not Allan’s assessment of the flaws in Roe v. Wade; it is the assessment made by the court’s majority. In effect, like its counterparts elsewhere, the Supreme Court must win its legitimacy every day by showing that it abides by the highest standards of cogency. The intensely controversial nature of these decisions only underscores the importance of that point. Yet for the myriad reasons I set out in my column (and which Allan does nothing to undermine), the majority’s reasoning cannot possibly be said to clear that hurdle.

A single illustration, drawn from my column, must suffice. In seeking to articulate a principle that could guide its decision, the majority asks whether abortion was generally or widely allowed in the United States in the decades that immediately followed the adoption of the 14th Amendment. Finding (contrary to the view of most medical historians) that it was not, it concludes that the Roe majority overstepped the mark in inferring a (qualified) right to abortion.

But were the relevant test the state of the law in the wake of the ratification of the 14th Amendment, there can be no doubt whatsoever that Brown v. Board of Education was wrongly decided, as school segregation was virtually universal in 19th century America. Since the majority repeatedly endorses Brown both as a decision of great merit and as a model for its own decision, the test it sets out is inherently flawed in ways it never even bothers to address.

Clearly, to say that the majority has not convincingly made out its case is not to suggest that Roe was a good decision; nor is it to deny that had Roe been decided differently, the issue of abortion might well have been much better handled in the United States than it has been – as I personally believe to be the case.

Rather, my point it is to stress the importance of respect for legal institutions within the West’s constitutional order – a respect which must, by the nature of things, be fragile and hence demands constant reinforcement. We cannot – at least in good conscience – excoriate the courts for sloppy reasoning when they take decisions we dislike but fail to chide them when they do so in causes with which we might otherwise sympathise.

In short, whatever the substantive merits or demerits of Roe, the unfortunate reality is that the Supreme Court has done itself, and the nation it serves, a great disfavour by undermining the quality of its jurisprudence and hence the respect which it will in the long run command. And the fact that it has, in the process, trampled on values conservatives have held dear at least since Burke, and opened the door for tomorrow’s ‘progressive’ judges to ignore precedent even more readily than they naturally would, compounds the damage.

As for Allan, ultimately, his objection is not to my column; it is to the American constitution which, rightly or wrongly, vests considerable powers in the Supreme Court – powers he believes are undemocratic. If democracy consists of nothing but majority rule, his position makes sense. Whether those of us who hold opinions, and profess religions, which have often been widely unpopular would want to live in such a ‘democracy’ is, however, another matter entirely.