There is no shortage of this kind of stuff. I note that you've tried to narrow the focus of the argument down to the "pray for X/prayer rally". I suggest instead taking a more comprehensive look at religion and US presidents. There are countless examples of things that an unbiased skeptic should find equally objectionable (or not) as those things you single out in Perry, including ones previously noted from Obama. A few more:
Jimmy Carter, 1976.
"I've wondered to talk about [my faith] at all. ... But I feel I have a duty to the country -- and maybe to God -- not to say 'no comment.'"
Bill Clinton, 1996.
"The Bible asks, 'If your child asks for bread, would you give him a stone? If he asks for fish, would you give him a serpent? If he asks for an egg, would you give him a scorpion?' Our children are what we give them, what we teach them. We dare not forget that basic truth. Their lives and our common future depend upon it."
Jimmy Carter, 1980.
"I suggest that when you get home, you get your Bible if you've got one -- I'm sure you have -- turn to Exodus 20 and read the Third Commandment. ... Well, don't forget now when you get home, read the Bible, okay? How many of you will look it up? Okay. Keep your promise."
George H. W. Bush, 1992.
"The other party took words to put together their platform, but left out three simple letters: G-O-D."
It's one thing for a politician to proclaim their faith. That, I have no problem with. I have no problem with a politician even showing up at a religious gathering (that she/he did NOT organize and run) and calling on god for help.
It is quite another when a politician makes a LEGAL U.S. GOVERNMENT proclamation to reserve a weekend to tell his citizens to pray for rain. Or to have his citizens go to a large prayer meeting that she/he organized while in office.
Once again, the problem isn't his religion, nor whether he prays in his office during the day. The problem is when he mixes religion with politics. He has no qualms of doing so.
Further, you haven't answered my question. To be fair, I'll say I wasn't clear. Let me make them more clear:
Show me where Obama (or Bush for that matter) said that his policies (any policies) comes from a directive from god.
Show me where Obama (or Bush for that matter) used his US Government elected office to create a pray for X day, or set up his own prayer rally.
Again, mentioning his religion is fine. Again, if Perry had said
"Well, obviously, Israel is our oldest and most stable democratic ally in that region. That is what this is about. Also, as a Christian, I feel that we should support Israel. So from my perspective, it's pretty easy."
I would have no problem with that. Even that shows that he is at least attempting to separate church and state. But to say,
"Well, obviously, Israel is our oldest and most stable democratic ally in that region. That is what this is about. I also as a Christian have a clear directive to support Israel. So from my perspective, it's pretty easy. Both as an American and as a Christian, I am going to stand with Israel."
He is blurring the line. And he has done so and continues to as governor. His past records show that he is not trusted as someone who can, or who may even be willing to, separate church and state.
This is directly important considering that part of the attack on 9.11 was to prove to the world that the attack was the beginning of a "holy war", i.e. Christians vs Muslims. Bush avoided anything close that could be mistaken as such. So has Obama. But Perry does not.
Is this him being naive? Or calculated? You know what, I don't care. You don't use the US Government to push a religious belief. Perry is consistent in doing just that.