Moral foundations theory explains why left and right often butt heads on every political issue under the sun. Our set of moral foundations, when viewed through a political perspective, can fall into two categories: social justice, equality, and fairness, or respect for authority, group loyalty, and moral purity. It’s no surprise then that the left and right can never agree on anything. The solution that pleases one group definitely won’t please the other and any bipartisan decision will likely have enough flaws in the eyes of the parties that they will both reject it. This theory is pretty common sense, and shows through things as overlooked as campaign slogans. Think of the moral bases behind “Hope” and “Make America Great Again.” They both have the potential to bring people together, just for different reasons.