Owen J. Roberts, Great Northern Railway Company v…
“ That the question is one of fact does not relieve us of the duty to determine whether in truth a federal right has been denied. When a federal right has been specially set up and claimed in a state court, it is our province to inquire not merely whether it was denied in express terms but also whether it was denied in substance and effect. If this requires an examination of evidence, that examination must be made. ”
