Brendan Carney Byrne considers the downfall of the Irish-American "mobster/politician/businessman":
"You can’t be a half a gangster," proclaims the tagline of Boardwalk Empire’s third season. One of the implications, besides the obvious ones for protagonist Enoch "Nucky" Thompson’s soul, as well as his career trajectory, is that the position of the politician and businessman who just happens to be a mobster is under threat. You can be a gangster, or you can be legit, but not both.
He argues that JFK's election marked the beginning of the end:
By [Boston gangster Whitey] Bulger’s heyday, the Irish mob had wasted away to a fraction of its former self. If JFK’s election had made Irish-Americans definitively mainstream, it also allowed them to take part in the White Flight in the ‘60s and ‘70s, leaving the ghettos and insular neighborhoods of major metropolitan cities for the suburbs. Boston and Hell’s Kitchen in New York City were two of the last homes of the good old-fashioned Irish-American stick-up man, and, by 1994 when Bulger fled an encroaching net of Federal agencies, even their time was over.
Just under two years before the eventual arrest of Bulger in June of 2011, Joseph Kennedy’s youngest child, Edward, died of brain cancer after a long and respectable career in the Senate. Though his personal character was certainly not untarnished, Edward Kennedy was never considered a crook. The contrast is apparent: Edward Kennedy was a politician and Whitey Bulger was a mobster. By the opening years of the 21st Century the category of Irish-American mobster/politician/businessman had disintegrated into disparate parts.