WHAT IT MEANS TO BE AMERICAN
Though the United States is a nation built by immigrants, nativism—the fear of immigrants and the desire to restrict their entry into the country or curtail their rights (or both)—has been a central strain in the national fabric from the beginning. Nativism waxes and wanes with the tides of American culture and politics, with some eras exhibiting more virulent anti-immigrant activism than others.
But few eras have exceeded the 1840s and 1850s, when a ferociously anti-Catholic, anti-immigrant, and xenophobic secret society grew into a nativist political entity called the Know Nothing Party and briefly dominated the politics of a handful of states by stirring up violent outbursts before imploding over the slavery issue in 1855.
Though the United States always enjoyed robust immigration, it was not until the 1840s and 1850s that it became a divisive issue in politics. ...