If Nixon scuttles the Apollo program in 1969, he loses 1972 by a landslide.
The Democrats (and probably most Republicans) would have crucified him, and rightly so. An overwhelming majority of the American people were solidly behind the idea of getting Americans to the Moon first. No matter what you think of his politics, he was first and foremost concerned about his image, especially if the Russkies beat us.
I have to believe he knew a decision of that magnitude -- no matter how he played it off as "tax savings" -- would have been a huge blow to the nation's psyche, as well as a massive hit to the military-industral complex that was involved in producing GNP and paying tens of thousands of people to do it. Those corporations which lobby really hard in Congress to keep our military No. 1 in the world.
It's impossible to explain how Moon-crazy this nation was in the mid-60s. Tang. Space Food Sticks. Walter Cronkite live from the Cape or Mission Control in Houston.
Almost everyone knew someone connected to the space program or had a friend of a friend at Boeing or McDonnell-Douglas or Rocketdyne or one of the hundreds of contractors working on everything from hardware to software to sewing patches on spacesuits. It wasn't just in Titusville or Houston or Huntsville. People were employed all over the country as part of the push to the Moon.
The hippy-dippies didn't vote, as McGovern found out. But Ma and Pa America did, and they were solidly pro-American, anti-Soviet. If that meant winning the Cold War by sticking a flag on a cold, dark, airless satellite orbiting the Earth, so be it.
Nixon would have had more success getting out of Viet Nam at that point than shutting down NASA.
Suppose Apollo 8 had been less than a total success. Suppose they got into earth orbit, there was an ignition problem with the S-4B, so they don't get the GO FOR TLI.
So they stay in orbit 10 days or so, essentially duplicating the flight of A7. They splash down and the astronauts are ok. But what does NASA do?
For public consumption, they probably say the flight was "largely successful," but in the halls of Houston, they'd be shitting bricks. The flight of Apollo 6 back in April (actually on the day of MLK's murder) had not been successful at all, they had major vibration problems with the second stage, almost lost the flight, and certainly would have aborted a manned mission.
So the NASA head honchos would say, hang on, time out, we have now had two flights in a row of the Saturn V which have been unsuccessful. They would still have had no successful flights of the Saturn V in addition to no successful flights of the Lunar Module with the deadline looming only 10 months away.
All this with the tragedy of Apollo 1 still etched in everyone's minds.
The lunar fever you describe did exist, but you know when it really burst into full force nationwide? Christmas Week, 1968. Before that, landing on the moon seemed like some kind of distant abstraction.
The nation was not transfixed by Apollo 7. There was kind of a national sigh of relief when it launched without a hitch -- it was pretty much the first major piece of national news in 1968 which wasn't an utter disaster -- and the live from orbit broadcasts had novelty value, but people were not huddled around the TV set watching every moment.
It took live tv photos from lunar orbit on Christmas Eve to do that.