Explain the two changes that rauch describes that weakened parties

Two ideas that Rauch presents as having caused significant harm to the political parties have a co-dependent relationship with each other. The first element Rauch identifies is the idea that what precisely defines the parties is no looser and "without boundaries". The other part that depends on this vagueness or larger gray areas of political representation, is the then ability within the parties themselves to select or elect the party leaders. As the increase in varied beliefs occurs within a party, the inability to select leadership increases, along with a growing lack of consensus on any idea.

Ther are many reasons.. is it a multiple choice?

C.25-28.. . .