On the other hand, if I had to choose between that candidate and another equally electable and qualified who sought guidance in prayer to God, I'd choose the latter.
Even if it's not relevant to you to have a president who prays to the true God, can't you at least concede that you can understand that it's important or at least potentially relevant to millions of Americans?
Well, as you can see, it's not irrelevant.
Now, let me press you. Who is the "true God" of your test? Only people within your denomination? If not, which denominations? Catholics OK? Unitarians? Mormons? How about Jews?
Well, God is not simply one who can be "found" [I can understand someone saying "I found Christ," but it's a little harder to comprehend when they say it about our Father in heaven]. We lost ones are the ones to be found, illuminated and brought into the light.
He must reveal Himself. He must reveal Himself to people. When God revealed Himself to Moses, He didn't arrive minus a "signature" so to speak. He left Moses His personal Name: "I am that I am" (Yahweh)--the Personal Self-Existent One.
Now, by comparison, study the official "first vision" of Joseph Smith. No such signature. We don't know exactly who these "personages" are that appeared to Smith. No names are given, other than one refers to the other as his son. (Likewise, Muhammad was visited by some personage in a cave. Who was this personage?)
Most importantly, God revealed Himself through a babe in Bethlehem, who in turn revealed Himself post-ascension to a man named Saul, who wrote most of the NT as a revelation.
So you ask which God matches the test?
As I review the Biblical scriptures, I see content consistency, especially when you consider how diverse the folks are who wrote it. (I mean you write getting a shepherd, a king, a tax collector, a doctor, some fishermen--men of all socio-economic stripes--and recruit them for them couple thou yrs--and then ask them to write on the most important spiritual and other topics in life...and then just see how random & disunified that would be). So that tells me that the God of these Biblical characters (versus say the God of the Quran or the God of Doctrine & Covenants or the Alien master beings say of Urantia) is the One to be prayerfully in alignment with.
Dr. Luke, in the Book of Acts, said that the Bereans were more "noble" because they searched the (OT)scriptures to see if what was said was true." (In other words, they searched the newer revelations by the older ones).
So, in this way we can compare newer revelations like the Quran to the older ones. If they don't line up, we need to reject it if we are to be Biblically noble. Same is true of the Book of Mormon and the D&C & the Pearl of Great Price, this latter one, for example, which proclaims that a "council of gods" exist out there. If the Bible doesn't mention a council of true gods, then if we are Biblically noble, we reject it.
Now you also mention various Christian denominations. I don't see them as different faiths; but rather, one faith...a diversity in unity like the God we serve. As for unitarians, they don't believe in a diversity in unity--only the unity. So, again, I compare their view to the older revelation. If a unitarian president would not pray to Christ, for example, then He's leaving out the creator of the universe to call upon (John 1; Colossians 1; Hebrews 1).