Look at his actions and the reactions of the public. Sanders is a political rockstar. People are more excited to see him than they are President Obama. Everywhere he goes the man draws a crowd, and the young generation cranes their necks to hear every word out of his mouth. He openly speaks out against Obama when he deems it is necessary and gets huge media coverage when he does. The way things are currently looking we're going to have a terrible president next year no matter how you slice it; people will be looking to Sanders for what to do. His campaign left a mark; he has incredible influence over the population and it is still growing. Sanders is and will continue to be the de-facto leader of the USA, president or not.