Actually there are two types of party system-two-party system and multi-party system. The reason why most country prefer the two-party system is because the candidate running under the banner of one of the two major parties has the higher to have a legitimate chance at winning a general election. That reinforces why the two major political parties in the United States have an incentive to keep it a two-party system. Democracy rely on the system enforce by parties involved. For that reason the leaders of all parties, old and new, urgently need to engage with their own grassroots and with the wider electorate to give politics and political parties back to the people and to prove that our multiparty democracy is the best means of securing political stability into the future.