D. Contain the spread of Communism in every region of the world
The domino theory said that if one country falls to Communism, then the nations it associates with will turn to Communism as well. So, the solution for this was try to contain Communism so it wouldn't spread.
The separation of powers example every branch of the us government get checked so none of them have absolute power
The Immigration and Nationality Act of 1965 got rid of the quota system for immigrants coming into the US. Before this act, there was only a certain amount of immigrants allowed into the US based on their nation of origin.
With this new act in place, immigration increased rapidly. This was especially true for individuals who were living in countries that were war stricken (like the ones in Southeast Asia). This increase in population probably worried some Americans, as individuals were coming from countries where the US was currently involved in a war (example- Vietnam). However, it really depends on the specific group of people you are studying as all American react differently to laws.
