What structure has become useless through evolution but still exists, typically in a much reduced form?

A "vestigial structure" or "vestigial organ" is an anatomical feature or behavior that no longer seems to have a purpose in the current form of an organism of the given species. Often, these vestigial structures were organs that performed some important functions in the organism at one point in the past.

Explanation:

the framers of the constitution insisted that federal judges be nominated instead of elected due to their desire to have judges above the shifting whims of the masses.

the hope, whether achieved or not, was that federal judges would only be beholden to the law and that by not having judges be elected, they would be protected if that law dictated an outcome that ran counter to popular opinion.