Federalism and nominating powers are the two factors that contribute to the decentralization of parties.
Explanation:
Federalism is the model of the trend of constitutional governing under which various states establish a union by a contract. According to this contract, a federal government and several state governments become different units of the union.
While on the other side, nominating powers, like big and famous names (who are known socially) affects the political parties. Big names are really helps in giving recognition and winning to the parties to which they are connected.