a technique for making 'Christian' and 'American' synonymous. He's making a claim about the nation. There's no avoiding that this is a strategic emphasis on his part. He didn't speak this way when he was at 60% public approval.

However, Obama generally doesn't use secular events to speak about how he came to Jesus, the core Christian testimony, says Domke, co-author of The God Strategy: How Religion Became a Political Weapon in America: How Religion Became a Political Weapon in America. It examined the God language of the four preceding presidents.

This is very different than Texas Gov. Rick Perry, who gave his personal Christian conversion testimony as part of a foreign policy speech Wednesday.

Perry speaking at Liberty University, the evangelical college founded by the late Jerry Falwell, staked the Christian claim for himself and for the USA.

According to the Associated Press, Perry said,

America is going to be guided by some set of values. The question is gonna be whose values? It's those Christian values that this country was based upon.

Voters think Perry is sincere. Whether they agree or they are terrified by his rhetoric, they think he means it. But, says Domke, when Obama -- the first multi-cultural, multi-racial president and the only one to mention unbelievers in his inaugural address -- speaks of God, in any setting, his authenticity is suspect.

Forget that he stepped onto the podium in Springfield, Ill., in 2007 to announce his candidacy for the presidential race after a Gospel choir sang and that his opening words gave glory to God. Forget that he's spoken of his personal salvation in churches and prayer breakfasts, Domke says.

For a Republican, you need a prayer rally. For a Democrat, you just need an opening prayer and more than that makes liberals nervous.

Questioning someone's religious sincerity is totally a factor of whether you already like that person. Baylor University sociologist Paul Froese says,

If Obama held a prayer rally, it would never work. People who don't like him won't believe him.

Froese, co-author of America's Four Gods: What we say about God and what that says about us, says his book's comment is true today: