There is a Christian narrative going around post-election that the next president has been appointed by God and that this is all part of God's plan. The narrative goes on to say that God works through flawed and immoral humans all of the time, just look at King David who had his friend murdered so he could be with his friends wife, Bathsheba. God still called David to lead Israel and used him to do God's work in the world! These excuses we make for our elected leaders (and non-elected leaders) lead us down a very slippery slope and happens to be a complete misunderstanding of King David and God's involvement in our world.
[The elders of Israel said,] "Give us a king to judge us like all the other nations have.”
Samuel was displeased with their request and went to the Lord for guidance. “Do everything they say to you,” the Lord replied, “for they are rejecting me, not you. They don’t want me to be their king any longer. Ever since I brought them from Egypt they have continually abandoned me and followed other gods. And now they are giving you the same treatment. Do as they ask, but solemnly warn them about the way a king will reign over them.” (1 Samuel 8:6-9)
To understand King David we must go back to the beginning of 1 Samuel. Samuel was a prophet who became a great leader of Israel. As Samuel got older, his sons had no desire to follow in their father's footsteps and it appeared that the line of judges and prophets was no longer working for Israel and so they demanded a king like the other nations. God had no desire to give them a king. In fact, God warns Israel in 1 Samuel 8:10-18 that a king will send their sons to war, enslave the people, take their wealth, and just be bad for the people. God knows that the desire for a king means Israel is attempting to replace God. But God relents and gives the people what they ask for.
The first king is Saul who is a man that lacks integrity, is dishonest, and prideful. Saul disobeys God's commands and eventually dies in battle. Meanwhile, David, as a young man, is demonstrating that he trusts God, is humble, and hopeful despite the evil in the world. His trust in God is demonstrated through the famous biblical story of David and Goliath. The people love David because of his character and faithfulness and so, he rises to power to become king.
1 Samuel uses these two kings as character studies and warnings to the reader. Saul is the warning, to be humble and reflect on our flaws. David is who we should inspire to be like, the one who trusts in God, is humble, and faithful. But, even David is flawed as we see in 2 Samuel. As mentioned before, David commits adultery with Bathsheba and then has her husband murdered. David is remorseful and confesses to these acts. God forgives him but there are consequences to his actions. His sons rebel against him, with one raping his daughter and the other trying to kill David to take the throne. All of which ends up with his sons dead and King David a broken man. If you want to hear the summary of 1 and 2 Samuel, check out the two videos below from the BibleProject.com.
All of this to say, God does not anoint our human leaders! God does not want us to have kings or presidents, God wants us to have God! Israel demanded a king despite God's warnings. Whomever the president is (or Senator, or Representative), is not part of God's plan! God's plan is the redemption of the world and bringing the kingdom of God to earth. God's plan was to come to earth as one of us in Jesus Christ, the Messiah. The human elected leaders of the time crucified him and murdered him. God's plan remained and Jesus was raised from the dead. God's plan is that you too will be raised from the dead and that the kingdom of God will reign on earth again one day.
Throughout all of scripture, God works despite humanly elected leaders and their sinfulness. David was loved because of his trust in God, strength, and humility. But even he (because he is human) sinned! People suffered because of that sin. This sinful side of David was not the man that the people elected to be king. And it was not God's doing. God only anoints what is good and oriented toward the kingdom of God. Period!
God does call each of us to specific things. But those callings are always towards the kingdom of God. The moment we sin and veer away from the kingdom, we are no longer following God's call. David was called by God to lead Israel, however, when he decided to sin, he was no longer following God's call on his life despite the fact that God's call put him in the position of power.
Whether it be Donald Trump, Joe Biden, or any other elected official, they are not our lord. They are not perfect. And they are not anointed by God. To say so borders on heresy. It is hard for us to say whether they have been called by God to the positions they are in, but one thing is for sure, as soon as they sin, the call is no longer one from God. This is precisely why God warns Israel about kings and why Jesus is our ONLY Lord and savior.