What role is played by a party’s national committee members?

Explanation:

Their most important role is in the presidential election, they are important to this because they are the ones responsible for setting up the nominating, in other words, choosing the president convention votes.

the constitution of the united states gave congress the absolute authority over immigration laws

this means that germany had to pay the allied countries. reparations are/is essentially payment for something that they have done wrong, so after ww1, germany was forced to pay reparations so they could replenish the allied countries resources' that they had lost during the war.