It's such a little thing but while reading the opinion I see that the court (Kagan in this case?) makes a factual claim it provides SOURCES. https://www.supremecourt.gov/opinions/25pdf/25-112_0am4.pdf "Modern cell phones, we observed a dozen years ago, are “such a pervasive and insistent part of daily life that the proverbial visitor from Mars might conclude they were an important feature of human anatomy.” Riley v.…
Most SCOTUS opinions are rigorously sourced. They’re usually also well argued. The recent spate being an exception, in particular anything written by Alito.
https://www.propublica.org/article/supreme-court-errors-are-...
So the sources exist, but whether they're quality is another question.