turning point. n. 1. a moment when the course of events is changed: the turning point of his career. 2. a point at which there is a change in direction or motion. 3. (Mathematics) maths a stationary point at which the first derivative of a function changes sign, so that typically its graph does not cross a horizontal tangent.
Because high Crimes and Misdemeanors was a term of art used in English impeachments, a plausible reading supported by many scholars is that the grounds for impeachment can be not only the defined crimes of treason and bribery, but also other criminal or even noncriminal behavior amounting to a serious dereliction of duty.
A well-constituted court for the trial of impeachments is an object not more to be desired than difficult to be obtained in a government wholly elective. As well the latter, as the former, seem to have regarded the practice of impeachments as a bridle in the hands of the legislative body upon the executive servants of the government.