There's no clear claim that any such oath -- or other law or guideline -- has been violated.
Consider this statement from Watkins' lawyer:
“It’s always disconcerting when a journalist’s telephone records are obtained by the Justice Department — through a grand jury subpoena or other legal process. Whether it was really necessary here will depend on the nature of the investigation and the scope of any charges.”
It'd look different if MacDougal were confident that the DOJ had violated process or law, including constitutional rights. As it reads, it sounds like he recognizes that right now, there's no apparent violations, and it's plausible that actions like this, disconcerting or not, may well be fully legal and justified.
Courts have consistently held that freedom of the press means freedom of the press-as-medium, not press-as-industry. Reporters have no more rights than you or I. What would the rationale be?
Consider this statement from Watkins' lawyer:
“It’s always disconcerting when a journalist’s telephone records are obtained by the Justice Department — through a grand jury subpoena or other legal process. Whether it was really necessary here will depend on the nature of the investigation and the scope of any charges.”
It'd look different if MacDougal were confident that the DOJ had violated process or law, including constitutional rights. As it reads, it sounds like he recognizes that right now, there's no apparent violations, and it's plausible that actions like this, disconcerting or not, may well be fully legal and justified.