Why did many immigrants come to the united states during the second half of the 19th century

Fleeing crop failure, land and job shortages, rising taxes, and famine, many came to the U. S. because it was perceived as the land of economic opportunity. Others came seeking personal freedom or relief from political and religious persecution. ... Immigrants entered the United States through several ports.

Explanation:

"a government in which power is divided between state and national levels". federalism is a system of government in which entities such and state and province, share power with the national government.