Of course, it was overtly and annoyingly Christian to some and many people, Perry invoking Jesus Christ and Christian theology and all that, but it's not without precedent. In fact, President Obama did so just this year, asserting the Resurrection as historical fact [!]:
“I wanted to host this [event] for a simple reason,” announced the president to a White House stocked with some of America’s most prominent Christian leaders. “During this season, we are reminded that there is something about the resurrection. Something about the resurrection of our savior Jesus Christ that puts everything else in perspective.”
Well. Not exactly what a Jew or Muslim was dying to hear.
Everybody knows that during the Founding era, presidents didn't talk like that. They preferred more generic terms for America's "civil religion," which might be safely described as "Providential monotheism." There's one God, not many gods, and He looks down on us and occasionally sees His way fit to gently guide history for the better:
"[I]t would be peculiarly improper to omit in this first official act my fervent supplications to that Almighty Being who rules over the universe, who presides in the councils of nations, and whose providential aids can supply every human defect...In tendering this homage to the Great Author of every public and private good, I assure myself that it expresses your sentiments not less than my own, nor those of my fellow-citizens at large less than either. No people can be bound to acknowledge and adore the Invisible Hand which conducts the affairs of men more than those of the United States."---George Washington, First Inaugural Address
To the Founders, God was a reality, not a theory. When Washington presumed to speak for "my fellow-citizens at large," this raised no controversy. But America's Deity to which he gave thanks was "the Almighty Being," "the Great Author," with an "Invisible Hand." Not Jesus the Christ, with all the doctrine that accompanies him.
And so, the irony is that here in the 21st century, while religion, religious conscience and Christianity itself are punked in various courtrooms as being inherently irrational, presidents and maybe-presidents are becoming more explicit in articulating Christian doctrine than the Founders ever found proper, even back when there were few Jews and even fewer Muslims thereabouts. [Let alone out-of-the-closet atheists---Ben Franklin said you could live to an old age in America without ever meeting one!]
For every push, there is a shove: you play Wack-a-Mole on God, he pops up somewhere else. Back when God was considered a reality, the details were largely left open. But now that God is legally only one theory among many---and an inherently irrational one at that, reduced to a "ceremonial deism" that not one Founder accepted, not even Tom Paine---it's really no surprise that a Rick Perry or even a citizen-of-the-world like Barack Obama feels obliged to show his cards to an electorate that wonders what the hell is going on.
NB: None of this is to say God even exists. We are all modern gentlemen, afterall, and gentlemen do not discuss such things. We are speaking of history, American history, of man and his questions and answers about God, not God Himself.
Although I meself have found that the name of God is on the lips of every drunk. But I admit haven't met them all yet. And Tom Paine, a true deist who rejected the Christian scriptures, even went to Revolutionary France and lectured against atheism. You could look it up. Even Tom Paine's deism wasn't just "ceremonial," and neither is America's.