Until that point, not even Nixon's fiercest media critics had laid at his door the suggestion that he was a felon. It was a needless denial that allowed opponents to hang the word 'crook' alongside the name of the president. It led ultimately to Nixon's resignation.
A week ago, a high-profile multi-millionaire businessman took the sensible decision in the prevailing economic climate to cancel a lavish charity ball for which he and his celebrity wife worked tirelessly to raise millions for deserving causes.
Interviewed by a journalist about it, the businessman, apparently needlessly anxious to establish the solvency of his business, committed a similar blunder. 'I am sitting in our £5m chateau in the Alps now. I will sue anyone who says my company is in financial difficulty,' he said. As far as is known, no-one was suggesting any such thing.
Again, it was a denial too far, elevating the story from a diary snippet to a sensationalist news piece. Worse, the quotes were lifted into the headline.
Unlike the late president, our modern high-profile businessman did not use the services of a PRO in delivering his response. Surely, had he made that investment, his statement would have been stripped bare of any righteous indignation and delivered coolly in the third person.
The art of denial is one of the most finely balanced double-edged swords in the comms chief's armoury. For it to be effective, denial should always be limited to addressing the core claim or allegation. It should never stray into any on-record disclaimer of wider issues.
Equally, successful rebuttal will depend on an intelligent mix of on and off-record material. The latter will almost certainly include quiet references to the certain, regrettable, use of litigation, should the denial not be heeded.
Accuracy and a plausible relationship with the truth are also key. Few PROs would want to subject their clients to the Clintonesque ridicule of a statement similar to that proclaiming 'I did not have sex with that woman' (Monica Lewinsky).
Focused, limited and accurate denial, delivered in the right time and context, can ensure that damage is averted or at least minimised. Palpable untruths, or denials of anything not alleged, will fuel new accusations.
Ian Monk is founder of Ian Monk Associates and was formerly a senior newspaper executive at the Daily Mail and The Sun