It was causing social tension. During the 1920s, the United States sharply restricted foreign immigration for the first time in its history. Large inflows of foreigners long had created a certain amount of social tension, but most had been of Northern European stock and, if not quickly assimilated, at least possessed a certain commonality with most Americans. By the end of the 19th century, however, the flow was predominantly from southern and Eastern Europe. According to the census of 1900, the population of the United States was just over 76 million. Over the next 15 years, more than 15 million immigrants entered the country. Around two-thirds of the inflow consisted of “newer” nationalities and ethnic groups'' Russian Jews, Poles, Slavic peoples, Greeks, southern Italians. They were non-Protestant, non-“Nordic,” and, many Americans feared, nonassimilable. They did hard, often dangerous, low-pay work '' but were accused of driving down the wages of native-born Americans. Settling in squalid urban ethnic enclaves, the new immigrants were seen as maintaining Old World customs, getting along with very little English, and supporting unsavory political machines that catered to their needs. Nativists wanted to send them back to Europe; social workers…