From Supreme Court Justice Harry Blackmun's papers, opened to public scrutiny in March 2004, historian David Garrow has uncovered the tale of a judge who, in Garrow's words, "ceded to his law clerks much greater control over his official work than did any of the other 15 justices from the last half-century whose papers are publicly available." Not only did Blackmun's assistants essentially compose some of his most famous opinions, but they openly allowed partisan concerns to guide some of their recommendations. For example:
[Clerk Molly] McUsic also took the lead in handling Planned Parenthood v. Casey, an abortion case that most observers believed could lead to Roe's demise because the recent replacement of Marshall with conservative Justice Clarence Thomas would create an anti-abortion majority. "The prospect of this case being heard has gripped the attention of the outside world," McUsic told Blackmun. "If you believe there are enough votes on the Court now to overturn Roe, it would be better to do it this year before the election and give women the opportunity to vote their outrage. The only harm would be that Roe would be overturned sooner rather than later. While under usual circumstances that harm would be enough to avoid hearing the case for as long as possible, the November Presidential elections may tip the scale in favor of hearing this case."
In a forthcoming Reason interview, Garrow notes that each justice had only one clerk prior to World War II, and that those were essentially secretaries; today they can have four apiece, and these assistants do an astonishing amount of the judges' writing. Among other things, this makes it easier for a man to stay on the bench when he's no longer healthy enough to do the work.
My favorite story of a clerk filling in for his boss comes from another Garrow article, published in the Fall 2000 University of Chicago Law Review. In the late '40s, Justice Frank Murphy was addicted to Seconal and then Demerol, and "some of his closest acquaintances were convinced that the Justice was regularly purchasing illegal drugs." He was hospitalized more than once, and during his departure instructed a colleague to cast his votes for him. In at least one case, "his" position was conjured by two justices and Murphy's clerk, working together to invent an opinion for the phantom judge.