Not only that, but, much as it shames me to admit it, the Irish American vote has been trending increasingly Republican, and even Trumpista in recent years. It is also possibly the most organised national lobby in the USA after the Zionists. AFAIK Hispanics don't tend to lobby for Spain, or Afro-Americans for African states, but the Irish lobby takes an active interest in Irish affairs and lobby accordingly.

Hence St. Patrick's day parades and White House ceremonials are one of the most important days on the US Political calendar. The English "special relationship" with the USA, on the other hand, is more of an elite and ideological thing, and thus doesn't have as much heft at the polling booths. During the Troubles, UK Diplomats regularly expressed frustration with their inability to prevent Gerry Adams et al fund-raising in the USA, and even having access to the White House.

I don't know enough about US political demographics to be definitive, but I suspect the Irish American vote was pivotal in enabling Trump win key swing States. His current net approval ratings in states he carried in 2016 are Pennsylvania (-7), Wisconsin (-13), Michigan (-12), Iowa (-12), North Carolina (-4), and Florida (0). Many of these states also have heavy concentrations of Americans claiming Irish roots:

In total 36M Americans claim Irish ancestry compared to 27M who claim English, but the English are predominately not located in Swing states.

Index of Frank's Diaries