If you have no interest in the Railway Labor Act or its arbitration procedures, skip this post.
The Supreme Court unanimously decided that under the Railway Labor Act, there is no jurisdictional requirement that the parties hold certain pre-arbitration proceedings, called "conferences." The arbitration panel erred when it held it had no power to decide 5 grievances because there was insufficient evidence of such conferences. However, the Court refused to consider the issue under the Constitution as a denial of due process. (I warned you to skip this post.)
The case is Union Pacific Railroad v. Brotherhood of Locomotive Engineers and the opinion is here.