Not sure I understand why the democrats would be terrified of one tweet? Granted it took them 4 years and every bit of evil and deception they could conjur, but they won, fraudulently or not, which to them is the same end ... why would they be terrified?
My thinking is that the Democrats are scared because they just got ran out of town. They know that Trump will get the support of over 74 million loyal voters to keep them on the run if he so desires. It would only take one tweet.