I have seen this loads of times as I read through court decisions and case law.
I am reading a Decision issued by an appeals court, and the judges cite a case that in turn cites a case. Here is the passage:
Our first task “is to determine whether the language at issue has a plain and unambiguous meaning with regard to the particular dispute in the case.” Barnhart v. Sigmon Coal Co., Inc., 534 U.S. 438, 450 (2002) (citing Robinson v. Shell Oil Co., 519 U.S. 337, 340 (1997)).
My question is, why bother citing Barnhart v. Sigmon Coal Co
at all, if ultimately, the thing we are interested in is really Robinson v. Shell Oil Co.
?