That's a pretty extreme judgment. First, there is no conflict between God telling Santorum to run, and telling someone else that Trump is going to win. Both are possible. They are not mutually exclusive.
Not exteme at all. In fact, saying God told you to do anything is extreme - and you should have the
fruits to back that up like the prophets and teachers had. A "quick" check would be to remember people actually chosen or in conversation with God really aren't sure of themselves, and often find the "work" they are called to do extremely hard and downright depressing. The reality is that a calling by God is like getting a direct order from a general about a mission: it isn't something you chose, and usually it will be extremely taxing and hard. But, it has to be done, and usually the prospect that wants it the least is the best for the job.
God never said there were no other gods; He said not to have any be for Him. How often have these people evoked "god's" name, but never said it was in the name of Christ/"Jesus"/(Hebrew variant of Christ's name)? If the spirits do not profess that Christ came in the flesh and was resurrected to life... they are of the Antichrist. Those are our clear parameters of discernment no matter how much we like someone's words.
Then there's the possibility of hearing wrong, or being deceived.
Then, they need better discernment of spirits, and they need to stop evoking the Most High's name with such confidence and (for some) arrogance. It is similar to people who make prophetic ststements without testing spirits. If they are wrong, the emberrassment of knowing they were deceived overcomes them, as God's prophecies are always spot on.
This is always a possibility, which is why we're told to judge prophecy before leaning on it.
It is irresponsible to bring the Most High into a carnal event such as an election - especially if you arent 100% sure. It is misleading. That is assuming the politician(s) have 100% sincere intentions.
The truth is that not all "gods" evoked by people are the same god. Some of them know this; some dont. Christ said that there are there are people who will say they knew Him and He will say He NEVER knew them. Politicians are humans capable of deceit, lies and swindling a population with demagoguery and flatteries. That is, often, their jobs in order to get votes and popularity. Just because someone says they are called by God to do or say something doesn't mean
1) they actually were, and
2) they are talking about the Most High God.
Ask them who God in the flesh was, and who is the savior of all humans on the planet. Ask them who Christ is, and whether or not He was resurrected to Life, and Is Life and is the Son of God. Test their spirits; ask them from where it came. Because, even demons know Christ exists, and tremble at His name.