I suppose that they are free to focus on readability when they don't have to structure their writing in order to defend their decision-making from anyone, being the highest court of the land.
A few points to the contrary: The primary purpose for their writing of opinions is not to defend the decisions, but to instruct lower courts on how they should reason on similar cases. So it very much matters on a practical level that their reasoning is sound. Second, if the goal is a cogent, defensible argument, readability is in support of that objective, whereas you suggest that readability is somehow (?) at odds with cogency and defensibility. Thirdly, the justices are keenly aware that the interested public consumes their opinions too, and that they are, in fact, ethically and morally bound to defend their decisions to the public.
> you suggest that readability is somehow (?) at odds with cogency and defensibility
All I am saying is that writing can be clearer and more concise when you don't have to include asides and digressions to preemptively defend it from criticism.
This is a technical point on power dynamics and writing style. When the authors are in a position of power, then they can focus more on readability (and cogency) and less on playing defense, because their court seats are secure for life.
By contrast, justices in lower courts are influenced by organizational politics and must focus more on defensibility, which may come at the expense of clarity.
So I do not find it surprising that the supreme court is able to produce more readable decisions than lower courts, because they have unique incentives.
> The primary purpose for their writing of opinions is not to defend the decisions, but to instruct lower courts on how they should reason on similar cases.
Correct. This is different from lower courts, which also explains why they are able to focus on readability.
Being the only non-democratically elected branch of government in a democracy, the courts don't enjoy direct approval from the people. So while the structure of the institutions seem to give them power, their authority ultimately hinges on whether people perceive their decisions fair and just.
When courts make unpopular decisions and can't explain why, there's always a risk of some constitutional crisis. If courts keep making decisions that they can't rationally defend, at some point their authority will begin to erode. (And if you followed the USSC rulings in recent years you might start to understand why. Maybe the resentment not yet directly targeted towards the courts, but those decisions did add fuel to the already divisive politics in the US.)
