"According to one of the leaders of the project, physicist Leonard Reiffel, hitting the moon with an intercontinental ballistic missile would have been relatively easy to accomplish, including hitting the target with an accuracy of about two miles."
Okay, then. That'll put a scare in them
(The Wikipedia article says the USSR thought about it, too. Luckily both sides had better sense, 'cos you know, if one had, the other would want to do so, too and next thing you know, the Moon would be totally unrecognizable and the Apollo astronauts would've had to wear lead longjohns.)