America was built on value and many American's believed that immigrants were changing America by changing its neighborhoods and trying to implement their own morals into the deeply engrained ethics of American society. Since immigrants were far to poor to move farther away from cities so they huddled together in the already stinking slums, where they were allegedly hard to "Americanize." This caused many Americans to think that America would no longer live up to its wonderful reputation as the land of opportunity, because immigrants were going to, slowly but surely, change the face of America.
Many Americans resented the fact that a majority of immigrants never really intended to become Americans and were merely in their country to earn money before they returned home to their families. Due to the fact that there was such a great inflow of immigrants there was always a lack of jobs, and many immigrants were considered to be strike breakers, as they would be called in to take jobs when worker had gone on strike. The resentment that American's felt towards immigrants would be amplified when they were unable to find a job, or wages were lowered because there were so many people willing to work for a small wage.
Another aspect that added greatly to the up surging or nativism in America was the World Wars. With the rise of the Kaiser and the Nazi party Americans became more and more anti-German. American opinion of Germany was already ill-disposed, but was further inflamed against the Kaiser and Germany when a German