The name for this idea is "Domino Effect" - this is a theory that says that if one country falls to Communism the neighboring countries would also fall to Communism, much like pieces of Dominos fall when a neighboring piece fell.
This theory was important in the Foreign politics of the US during the cold war.
Declaration of independence
The One-Person One-Vote Rule refers to the rule that one person's voting power ought to be roughly equivalent to another person's within the same state. The rule comes up in the context of Equal Protection. The most relevant Supreme Court case is Reynolds v. Sims, 377 U.S. 533 (1964).
D. 1824 is the answer he was elected then and his presidency was 1825-1829
