God is the one who decides who is genuinely born again as Christian, but there are lots of verses telling us to watch out for them, because he expects us to be vigilant.
Bush, for example, claimed the description but lied about Iraq to get the nation into a war that killed thousands of Americans and 100s of 1000s of Iraquis. He created the “faith-based” ministries to entice gullible Christian ministries into taking it to later use against them.
One famous scholar (Montesquieu maybe?) wrote that the way that governments get religions to do what they want is not ordering them to obey, but by “helping” them. Follow the money.
“Wherefore by their fruits ye shall know them. ” – Matthew 7:20
In the case of Skull and Bones 41 (Bush Sr.), he was a scoffer and a Christian in his White House blew the whistle on him. With Obama and the Clintons it’s more obvious. Should be I should think to any genuine Christian at least.
There’s a verse I can’t remember right now also about how the spirit of one can recognize the Lord’s spirit in another, but I knew some people of whom it manifested. But I think that takes some time learning the word to get to that point.
A missionary couple in Colombia, for example, dining just before leaving one town, felt drawn to speak to another couple dining there, they thought it was to share the gospel. But it was another missionary couple.
In another case I heard of, a guy landed in a town in Italy but lost the address of the missionary home he was to join. Walking downtown along the street, he turned around to look at another guy who had just passed him with his wife, who also turned around, they looked at each other for a minute then approached and smiling, they knew each other though they had never met.
I also “accidentally” ran into somebody I knew in Miami in a similar situation, though less dramatically.
On the other hand, in my only encounter with a Jesuit priest, that guy had an evil and hateful spiritual aura that was thick and palpable (to me and my companion) in his presence, aimed at me and my witnessing partner of course.