According to Tony Messenger's blog at stltodaycom, Nixon made a similar pledge but when asked about it by a fellow-Democrat, Nixon stated, "What I said was very precise . . . I do not have any plans' to raise taxes." In case we didn't catch the nuance, Nixon repeated himself stating, "I have absolutely no plans for any tax increase."
A Democrat saying that he doesn't plan to increase taxes is like me saying that I don't plan on eating that last piece of chocolate cake. It is a statement of good intention only, not commitment or philosophy. Don't count on it when push comes to shove.
Nixon's spokesman is backpedaling and making the no-tax-increase pledge on his boss's behalf. But until the candidate makes an unequivocal pledge himself, without mincing words, how could we hold him accountable if he "changed his mind?" And how could we elect him?