It wouldn't have been at all surprising if Kerry had stopped there, limiting his God-talk to policy metaphors. Instead, he decided to take on the God gap directly:
And let me say it plainly: In that cause, and in this campaign, we welcome people of faith. America is not us and them. I think of what Ron Reagan said of his father a few weeks ago, and I want to say this to you tonight: I don't wear my own faith on my sleeve. But faith has given me values and hope to live by, from Vietnam to this day, from Sunday to Sunday. I don't want to claim that God is on our side. As Abraham Lincoln told us, I want to pray humbly that we are on God's side. And whatever our faith, one belief should bind us all: the measure of our character is our willingness to give ourselves for others and for our country.
Nearly every phrase in this was politically well-calibrated. Citing Lincoln and Reagan, he's engaged in innocence by association. By saying he doesn't wear his faith on his sleeve, he tried to turn a perceived weakness into a virtue and imply subtly that Bush's religiosity is partly tactical. The idea that faith has informed his values "from Sunday to Sunday" was not only lyrical but also a way of pointing out that he's a regular church-goer. And the line about being on God's side and not vice versa is a direct slap at Bush's one faith-based vulnerability: the slight suspicion that he feels like he's been personally anointed by God. The one line that seemed off to me was "we welcome people of faith," which implies that they are an outside group whose support he'd like (like veterans or soybean farmers). An obvious Republican comeback: "They welcome people of faith. How nice of them. We ARE people of faith."
But the most important aspect of Kerry's faith talk—the element that makes me think it might be an electoral turning point—was the campaign's connecting of his faith and his Vietnam experience. The danger for Kerry in talking about faith was always that he'd seem inauthentic. The campaign was well aware of how foolish Howard Dean looked when he tried to seem religious by discussing that great New Testament book of Job. They had to find some way of talking about faith that tied more naturally to his biography. Vietnam was the obvious way to do it.
The faith-in-battle imagery succeeds on another level. Bush's religious talk works in part because it's part of a redemption narrative. Due to his drinking problem, he was fallen (or falling down). He found God and was saved. He had an obstacle, he suffered, and faith helped him to overcome. In Vietnam, Kerry, too, faced obstacles, suffered, and overcame, in part because of his faith. In some circles, the dodging-bullets-with-the-help-of-God metaphor might seem even more impressive than the detoxifying-with-the-help-of God one.
Kerry's certainly not in the clear on this yet. He can quote the Bible to tee up every new tax credit proposal and he still won't win over many conservative Catholics who loathe his position on abortion, especially partial-birth abortion. Many religious voters are motivated by ideology more than theology and will find Kerry too liberal regardless of how often he prays the rosary.
But on balance, Kerry took a major step toward convincing people that it was OK to believe in God and Democrats at the same time.