There you go again, making judgements off a single tweet - whether or not Trump is an idiot is immaterial. He's useful, which is all that matters to the discerning Christian.
If you were only interested in discernment, you wouldn't even talk about Trump the person. You'd just say, "That's a bad tweet, wonder why Trump posted it?" Because a nonjudgmental person does not assume things of others, he asks questions, but he does not pretend to know the answers only God knows. What is in a person's heart is only for God to know - unless a person is so blatantly wicked, with vile acts of murder, rape, and theft. That's pretty much the only time we can know and judge.
We will be judged according to how we judge others - would you want to be judged because of a single tweet? Who cares - it's just a tweet. Trump is a busy man I guarantee you he doesn't think too hard about every tweet. Sometimes he does, when he makes a "statement," but most of the time he shoots from the hip until he gets a bullseye.
It's a fact that Trump isn't a deep thinker as much as he is someone who relies on good instincts. That's not an idiot nor a savant, he gets good results and that should be more than enough for any Christian in this day and age.
