Answer:
push factor
Step-by-step explanation:
A push factor is a term that is related to the migration of people from one country to another. This term refers to the falha that a country has in maintaining a group of people within its territory, keeping them unhappy and oppressed for some reason and forcing them to migrate to another country in search of a better life.
An example of this can be seen in the question above, where it shows that the Jews left Russia for the USA in 1800 because Russia allowed them to suffer religious persecution.