2.Why only two parties in the U.S. a.cultural reason:the black and white/right and wrong type of thinking (partly influenced by religion) b.the single-member/simple majority electoral system 3.The consequences of the two-party system? 1)party responsible system 2)Both parties have to broaden their appeal and move to the middle.To win general elections,both parties have to seek the political center.There are factions within each party:conservatives and liberals in both parties. Are there differences between the two parties or do political parties matter in American public policy-making? The answer is yes and no.Yes,because there are policy differences between the two parties.No,because differences are really not that big.Also they both have to move to the center.In addition,the economic system2. Why only two parties in the U.S. ? a. cultural reason: the black and white/right and wrong type of thinking （partly influenced by religion) b. the single-member/simple majority electoral system 3. The consequences of the two-party system? 1) party responsible system 2) Both parties have to broaden their appeal and move to the middle. To win general elections, both parties have to seek the political center. There are factions within each party: conservatives and liberals in both parties. Are there differences between the two parties or do political parties matter in American public policy-making? The answer is yes and no. Yes, because there are policy differences between the two parties. No, because differences are really not that big. Also they both have to move to the center. In addition, the economic system