The film is, obviously, named the same as the reference novel by Tom Clancy which, itself, is named after the Irish ballad The Patriot Game.
"The Patriot Game" is an Irish ballad with lyrics by Dominic Behan and a melody from the traditional tune "The Merry Month of May"
The song concerns an incident during the Border Campaign launched by the Irish Republican Army during the 1950s....It tells the story of Fergal O'Hanlon, an IRA Volunteer from Ballybay, County Monaghan who was killed at the age of 20 in an attack on Brookeborough Royal Ulster Constabulary barracks in County Fermanagh on 1 January 1957. The operation was devised and led by Sean Garland, an IRA man from Dublin. Another volunteer, Seán South from Limerick, was also killed during the raid.
The song is one of the best known to emerge from the Irish nationalist struggle and has been popular amongst the IRA.
The movie (and novel) relate the plot by the IRA to exact revenge on Jack Ryan after he foiled an assassination plot.