Michael Sanera in his post below cites Madison writing in the Federalist Papers on the issue of whether the supreme court might have a bias in favor of the federal government in cases where the line between state and federal powers is in dispute. He notes that Madison recognized the potential problem but goes on to state that “But Madison argued that the potential bias of the Court in favor of the federal power would be counteracted [because] the Constitution contains an appointment process for justices that would help to insure the Court?s ?impartially.?
At the time of Madison this was especially true because senators, who must approve supreme court nominees, were appointed by state legilsators and not elected. Madison did not forsee the 17th Amendment.