We still have eight Justices on the US Supreme Court, so there will surely be further cases this term where we will see the court equally divided.
Of course, even with a nine Justice court there are such moments, as when one Justice recuses himself for whatever reason and the non-recusing justices split evenly.
But one case in 1939 stands out as an oddity. All nine Justices participated in a case concerning the very controversial matter of the child labor laws (this was two years after the "switch in time" and the consequences of that '37 jurisprudential shift were still being worked out). The Justices decided that the case involved three distinct issues of law. They then voted 5-4 on one of those decisions, 7-2 on the second, (so plainly nine Justices were each voting) and then declared themselves "equally divided" of the third issue, so they took no position on it.
This has left historians scratching their heads ever since. Presumably one of the nine declined to vote at all on that third issue, and the others split 4 to 4. So: can one describe this as one third of a recusal? And who was the missing Justice?
A recent Legal Research Paper from Notre Dame Law School goes into this head scratcher in some depth.
The case was Coleman v. Miller, and the underlying controversy concerned the Child Labor Amendment, a constitutional amendment that had been sent to the states in 1924, without expiration date, allowing Congress to regulate the labor of persons under 18. The Amendment has never been ratified, indeed the jurisprudential success of New Deal legislative measures made this proposed change to COTUS seem moot. But as of 2017 it still may be considered pending. Ratification by ten states would bring it into force.
Controversy arose in Kansas, after that state's ratification. The state senate had split evenly and the Lt Governor had cast a tie vote in favor of ratification. Opponents of the move cried foul, and sought a writ of mandamus declaring that a tie vote broken in that way is NOT a ratification vote under the procedures set out in the US constitution, so interpreting the word "legislatures" in the Article V language, "when ratified by the legislatures of three-fourths of the several states...." to exclude an executive official such as the Lt Gov.
Separately, the petitioners wanted the court to rule that the proposed amendment had failed, in that it had not been ratified within a "reasonable time," and thus it was no longer before Kansas.
The Kansas Supreme Court found, as a threshold matter, that the unhappy anti-ratification legislators did have the standing to bring this petition. But on the merits it found against them.
The court below upheld the ratification. The SCOTUS addressed three issues:
1. Whether the members of the state legislature who had voted against the ratification had standing to bring the petition for a writ;
2. Whether the court below was right to find that the alleged staleness of the amendment was a non-justifiable political matter;
3. Whether the classification of the Lt. Governor as a member of the legislature of the state or not is itself a justifiable issue?
SCOTUS found, as to the first point, by a vote of 5-4 that the petitioners did not have standing. It presumably could have ended its inquiry there, but it continued, finding 7-2 (with only McReynolds and Butler dissenting on this point) that the proposed amendment remained subject to ratification. It made no finding on the classification of the Lt. Governor, because on this point as Chief Justice Hughes opinion says, the members were "equally divided."
That tie of course didn't do the anti-ratification litigants any good. The bottom line was that the high court found "no reason for disturbing the decision of the Supreme Court of Kansas in denying the mandamus sought by petitioners...."
So: as a matter of historical inquiry one is left with the question: how did that final issue come up a tie? If it was because someone left the building (literally or figuratively before a third vote was taken, who was that someone?