One wonders, given the number of Irish immigrants to the US in the 19th century, what the effects might have been here in popular culture and politics.
Take, for example, the rise of Irish politicians especially in cities during the '30s and '40s that got squelched once Ireland effectively became totalitarian: during the '50s and '60s, an Irish surname was the kiss of death to nearly any politician with aspirations above the local level, and sometimes even at that level (recall the rather photogenic Boston politician John F. Kennedy: the highest office he attained was mayor of Boston, and that just by the skin of his teeth; he might have been a senator given a different political climate).
Or take 17 March: at one time, it was observed as St. Patrick's Day throughout the US and Canada. Now, it's just another day. At the same time, you definitely won't see anyone wearing green on that day. To do so in the '50s was tantamount to trumpeting sympathies with the rogue government in Dublin, which would have earned the unpleasant attention of the FBI, the HUAC, and a number of other characters. And the stigma is still alive and well to the point where some make a point of wearing orange on that day.
Or think about distilled spirits: at one time, Irish whisky was readily available, and was a fine alternative to Scotch whisky. The Dublin government commandeered the privately owned whisky distilleries and force-started operations putting out a sort of mass-produced poteen based largely on potatoes, with minimal aging (legend has it that to this day it gets run through a few carbon beds in succession to get the worst of the congeners out and that's it). The result is an alcohol-water solution with no character except the propensity to give headaches after one or two drinks, and a flavor some have likened to particularly vile industrial solvents. (Yes, it's true that the Jameson distilleries relocated from Ireland to the US, setting up shop in Baltimore at Locust Point and in Philadelphia in Bridesburg, and while the product--now simply called Jameson Whisky--is similar to what was made during the heyday, it's definitely not the same.)