Mark 16:17
And these signs shall follow them that believe; In my name shall they cast out devils; they shall speak with new tongues;
Just because Christ paid the sins does not mean humans are suddenly immune from demons, if you don't have Christ in your heart demons are working on your life either within you or oppressing you from the outside via addictions/anger/death etc....
Athiests may scream at the top of their lungs that they don't believe in anything but the Bible clearly says in 1 John that any spirit that does not confess that Jesus is the Christ is the spirit of anti-christ aka satan/demons....athiests are unaware that by denying Christ they open themselves up to demonic influence.....
Plus why would Jesus say in Mark in my name they will cast out devils? he said this future present tense b/c he knew the world would only get worse and more demons would be running around then ever before....
History even proves that the most "effective/popular" leaders were mostly demon possessed/influenced....Hitler was influenced by black mysticism, nero by his hate for Christianity and wanting to restore roman god religion, Nimrod trying to defy God with the tower of Babel? These are all demon influenced people whether you want to admit it or not....to simply dismiss demonic activity as not having an effect on any human especially Christian is naive and dangerous...we must always be on guard b/c the adversary the devil is looking to eat us alive and make us fall.....
Lest you say I'm being unfair, Trump may also be demon possessed...we don't know b/c haven't seen any manifestations but politicans are just sinful humans and fair game for the spirit world as all other flesh humans are as well....