How have immigration policies changed throughout history in the us

Americans encouraged relatively free and open immigration during the 18th and early 19th centuries, and rarely questioned that policy until the late 1800s. After certain states passed immigration laws following the Civil War, the Supreme Court in 1875 declared regulation of immigration a federal responsibility.

The league of nations was found in 1919 to keep peace after world war l.but it failed to prevent world war ll in 1939,so in 1945 the nations of the world set up a new organization,the united state (un).since then, the un has encouraged international cooperation and worked to resolve conflict