More to the point – based on my reading of Nixonland, by Rick Perlstein – he was not an honest man. He had a sincere dedication to public service and he had a kind of integrity, but his integrity never included honesty. And specifically he never accepted, in practice nor in theory, any notion at all that a politician is obliged to tell the truth to the public. His attitude was always that those in-the-know will make the decisions and “the public will be told what the public needs to be told.”
When Nixon was in the Navy he made a lot of money playing poker. He was a very good poker player. He had the all-important skill of dissembling his true position/intentions to other players, bluffing, keeping the poker face – which is not exactly a dishonest thing within the setting of that game, but he seems to have assumed it would be as appropriate and would serve him as well in political life.