“Remember,” said Ronald Reagan, “we have opponents; we don’t have enemies.” That’s why President Reagan was so successful in gaining the respect and affection of the American people. Even people who did not like his policies liked him. President Obama’s troubles in office stem in no small part from is willingness to treat American opponents as enemies. (He treats America’s true enemies as friends, but that’s another matter.) The readout from Election Day is that Mr. Obama’s Democrats suffered “a massacre.” That word from Britain’s prestigious Economist is being used even as Christians and Muslims in Syria and Iraq are...