What evidence exists of criminal activity within the executive branch over the past 53 years?

There have been several instances of criminal activity within the executive branch over the past 53 years. Some examples include the Watergate scandal during President Nixon's administration, the Iran-Contra affair during President Reagan's administration, and the impeachment of President Clinton for perjury and obstruction of justice. Additionally, there have been various investigations and allegations of corruption and misconduct involving other presidents and their administrations.