Returning to the subject of that 1927 movie The Callahans and the Murphys (Diary, June 28th), one of the reasons it hit such a raw nerve with Irish-Americans is that coincided with an upsurge of protests by the Ku Klux Klan. In May of that year, at a parade in New York, 1,000 robed Klan members rioted when police tried to prevent them marching. The NYPD was heavily Irish then, a fact not lost on the KKK. Handbills posted in Queen’s after the riot bore the headlines: “Americans Assaulted by Roman Catholic Police of New York City. Native-born Protestant Americans...