My favorite part of his speech, which is linked here, was this quote by John Adams.
"Freedom requires religion just as religion requires freedom. Freedom opens the windows of the soul so that man can discover his most profound beliefs and commune with God. Freedom and religion endure together, or perish alone."
This is exactly why America stands for freedom around the world. If people are free to worship as they please, then the Gospel of Christ can be shared openly, without threat of persecution.
As to Romney as a candidate, I think he could do it. Although, beating Hilary is going to be almost impossible. But if the Evangelical vote can swing to Romney, then maybe there's a chance.