by John Marshall Harlan, Snyder v. Fiedler — Opinion of the Court
“ In the courts of the United States no person can be excluded as a witness in a civil action by reason by being 'a party to or interested in the issue tried' except 'that in actions by or against executors, administrators, or guardians, in which judgment may be rendered for or against them, neither party shall be allowed to testify against the other as to any transaction with or statement by the testator, intestate, or ward, unless called to testify thereto by the opposite party or required to testify thereto by the court.' Rev. ”
