Several years ago, PBS had a documentary whose name I can't remember,
but I think that is was simply an American history of the year 1968.
According to that documentary, NASA sent Apollo 8 to the moon, because
the CIA told them the Soviets were about to beat us to that goal.
Their original plan was just to continue doing docking rehearsals in
Earth orbit with the LEM.

I've always wondered if the CIA gave the alarm because they had
reconnaissance photos of the N1 on the pad, before the big explosion.
It turns out that, although it wasn't the famous mega-explosion, the
N1 did have it's first launch failure on 2/21/69, which was just two
months after the Apollo 8 Christmas flight, in1968.

I'm going to continue assuming that my theory is correct, and that the
CIA's photos were of the N1 being prepared on the pad for its first
test flight. They had good data, but as usual they didn't know how to
interpret it, because espionage is mostly guesswork and assuming the
worst. The Soviets were about to try to launch, but they were nowhere
near beating us into space.