How was it possible for some few US Presidents who seemed to be on a Divine mission (JFK, Lincoln, Washington perhaps) to win their elections when the Extraterrestrial Alliance has always been in control?

To be open and honest in answering your question, we can tell you that sometimes human choices prevail in spite of the aims of the Extraterrestrial Alliance. All it takes is for the Alliance to be lackadaisical, which is not hard for them because they always have the upper hand unless they let their attention wander for too long and human choice rises up and makes something happen before it can be headed off and blocked. There have been cases where human cheating saved the day. In a sense, it is a blessing when this happens if it ends up saving human lives. So karmically, it is a negative but in such a case would be the lesser of evils. It is hard in physical existence form to never make a mistake and never cause harm to something or someone, including the self, so all get in arrears with the Law of Karma. It is then a function of how the ledger balances with good deeds and acts of loving kindness that can counterbalance the errors, mistakes, and willful harm to others a person may be responsible for.