Tale of 1984 Irish assassination attempt on Reagan is told

I ran across an interesting story by Kerry O'Shea of the Irish Central about President Reagan's visit to his ancestral home of Ballyporeen in 1984.  Apparently a man attempted to shake Reagan's hand while concealing a piece of broken glass in his hand.  The attempt was, of course, thwarted.

Disappointingly, both O'Shea's piece and a post he cites by Barry Duggan and Ralph Riegel fail to elaborate on the reason for the assassination attempt beyond the phrase, "The man...wanted to confront Mr Reagan over US foreign policy controversies."