Ah yes, sorry for not giving a shout out to the kiwis.
But as Clausewitz said, war is politics by other means. Victories can only take you so far-you need a competent game plan and "good politics" and good PR as well. Not to mention the will to do what it takes, the ability to be honest about whether it is worth it BEFORE starting the mess, and being blunt with the people about your goals and what it will take. The problems in PR wouldn't have been near as bad(at least) if the credibility gap never occurred, if Johnson had been more honest and clear. He didn't want to distract from the big stuff for him-the Great Society, Civil Rights and thought he could do everything on the "cheap" and just bluff the American people until it all worked out OK, which of course it wasn't going to. This was a big error.
He was putting domestic tactics in foreign policy, which was a big no-no. Ironically, Nixon did the opposite. There is also one other yin yang difference I think. Johnson was way too optimistic, trusting of others, and confident in himself. An idealist in office, albeit a wily, ruthless politician achieving these idealist goals. He thought he could do everything well, even stuff like foreign policy that he wasn't interested in or suited to. Nixon was the opposite-way too pessimistic, untrusting of the people-a classic "realist". He expected the worst out of people and often got it as a result. His ability to be unsentimental and to deal with people while KNOWING they will still hate and be in competition with you was great in foreign policy(whereas Johnson wanted to win everybody over, and thought he could treat Ho like a Congressman), but domestically, with "enemies" blown out of proportion... that led to stuff like the Plumbers. He treated everybody like a foreign enemy.
I remember one quote that Phil Caputo made in the 90s to an aging Vo Nguyen Giap, when he pointed out the Americans won pretty much all the battles. Giap replied, "Yes, they did. And in the end, it didn't make any difference." A similar conversation came during the fall of Saigon from a Marines officer to an NVA officer, I believe.