There was indeed a great deal of overlap between the nativist and prohibitionist movements. The Anti-Saloon League, the most vocal prohibitionist organization in the country, was led mainly by Protestant ministers, most of whom were concerned that the religious and moral character of the United States was in peril.

It was not only the pernicious effects of alcohol that concerned them, but also that alcohol was of central importance to the social life of the millions of Catholic immigrants who had come to the country since the mid-19th century. The urban saloon was not merely a retailers of beer or rum – it was a place for the working man to socialize, and an arena where immigrants could organize themselves politically.

In particular, the tavern was associated with Democratic urban political machines such as Tammany Hall. The advocates of prohibition, meanwhile, tended to find their home within the Republican Party, and viewed the cause of temperance as being inextricably tied together with attempts to clean up corruption in urban politics – which was in turn caused by the clannish tendencies of immigrants and the degrading effects of drinking.

Once the Volstead Act was introduced, furthermore, it highlighted the status of immigrants as law-breakers while also infusing nativism with an added moral dimension. Various immigrant organizations had opposed Prohibition – notably the National German American Alliance, which represented German-American brewers (and which was tarred with the brush of disloyalty because of World War I) – and Catholics and Jews were disproportionately involved in rum-running and clandestine sales of alcohol.

Given the difficulties of enforcing the Volstead Act, many of its supporters turned to vigilante action, which was typically directed toward immigrants. The Ku Klux Klan was revived as a fraternal organization in the 1920s, choosing Catholics and Jews as its main targets. This reborn Klan was strongest in areas where Prohibition had the greatest support – not merely in the South, but also in the West and Midwest.

The Klan supported both immigration restrictions – culminating in the Johnson-Reed Act of 1924, which effectively put an end to the period of mass migration that had begun in the 1880s – and tighter enforcement of Prohibition regulations. Chicago Lawyer Clarence Darrow told the Baltimore Sun in 1924 that the “father and mother of the Ku Klux is the Anti-Saloon League. I would not say every Anti-Saloon Leaguer is a Ku Kluxer, but every Ku Kluxer is an Anti-Saloon Leaguer.”

Governor Al Smith of New York came to a similar conclusion about the Democratic Party convention of 1924: “the Klan and the anti-saloon forces in the convention were practically identical.”

Not all supporters of Prohibition were necessarily nativists, but given their ideological similarities they made natural allies.