Facebook is the most popular social networking website. Every post on Facebook actually can imply the user's emotion or opinion. In this paper, we present our analysis on posts associated with left- and right-wing politics in the United States of America. Our dataset contains posts several related Facebook fan pages. We analyze sentiment of posts for the prediction of left- or right-wing politics. We build sentiment features for the prediction and evaluate prediction performance. The results show that F1-score can be as high as 0.95 when TF-IDF is used with a decision tree. Posts generally involve emotional words. We use the lexical databases for sentiment analysis. Our experiment results show that the sentiment analysis is sensitive to some classification algorithms.