Closest relationship from this list is Oliver Wendell Holmes -- 7th cousin, 4x removed (making 18 degrees of connection). Interestingly, my grandfather had an uncle who argued a famous case before Holmes.
However, the closest relationships to Supreme Court justices that I am aware of is not to any of the listed justices but rather to the two John Marshall Harlans. John Marshall Harlan I, 4th cousin 5 x removed) -- the "Great Dissenter" in the Plessy vs. Ferguson case, and his grandson, John Marshall Harlan II (6th cousin, 3x removed), whose ascession to the court was intentionally delayed by southern Senators to prevent him from being seated in time to participate in the Brown v. Board of Education case.
