At the U.S. Supreme Court, Justices let other Justices know that they are signing on to an already-circulated draft opinion by sending around a “join memo.” The join memo usually just says that the Justice wants to join the opinion, sometimes with some suggestions for possible edits.
Different Justices have different standard lines they use for join memos. Some say something like, “I would be pleased to join your opinion.” Others use the more traditional (if rather odd) sentence “Please join me,” the idea being that the author of the opinion will then “join” the other Justice to the opinion.
In light of that, I was amused to read in Walter Murphy’s book “Wiretapping on Trial” that apparently Justice Holmes was a fan of more flowery join memos. According to Murphy, Holmes once joined an opinion of Chief Justice Taft by writing, “I cling to my preceptor’s hand and follow him through the dark passages to the light.” Murphy at 98. I guess “I agree” just wouldn’t do.