This US Supreme Court case involved a dispute between the Mayor, Recorder, Aldermen and Common Council of Georgetown (appellants) and the Alexandria Canal Company and William Turnbull (appellees). The appellants argued that they had exclusive rights to regulate navigation on Rock Creek in Washington D.C., while the appellees claimed that Congress had granted them permission to build a canal along Rock Creek which would be navigable by boats. The Supreme Court ultimately sided with the appellees, ruling that Congress did indeed have authority over navigational matters within its own district. Furthermore, it was determined that any acts of local government attempting to impede upon this power were invalid as they could not supersede federal law. This decision established an important precedent for future cases involving disputes between state governments and federal authorities regarding jurisdiction over waterways within their respective boundaries.

In the dissenting opinion of The Mayor, Recorder, Aldermen and Common Council of Georgetown v. The Alexandria Canal Company and William Turnbull (1838), Justice McLean argued that the Court should not have granted a writ of mandamus to compel the Appellees to pay damages for their construction project on public land. He believed that it was up to Congress or local legislatures to decide if compensation was due in such cases, as they are better suited than courts when it comes to matters involving public policy. Furthermore, he noted that there had been no prior precedent set for granting a writ of mandamus in this type of case; thus doing so would be an unprecedented move by the court which could lead other parties with similar claims against municipalities seeking relief from judicial tribunals instead of legislative bodies. Ultimately, Justice McLean concluded his dissent by stating that while he sympathized with Appellants’ grievances over their loss caused by Appellee’s actions, he did not believe it was within the power or jurisdiction given to him as a justice on this court issue any form relief through a writ of mandamus.