re: To convince
Once, a president made a speech about choosing to go to the Moon.
Not once did he mention the Soviets in his speeches,. He was adressing his nation and asking it to answer to the challenge.
He was handsome, eloquent...but one day was shot and became a legend.
All those things have helped somehow, and also the fact that nobody had done it before.
Of course, the context is very different today and in many ways it should be a lot easier. It's not another side of an iron curtain that challenges the US anymore, it's its population.