FIFA, football's world governing body, last night closed the door on Ulster-born players turning out for the Republic.
It follows the recent tug of war between the IFA and the Football Association of Ireland over Derry-born Manchester United defender Darron Gibson.
Although the 19-year-old will not return to Northern Ireland's ranks, having already played for the Republic, he will be the last player to defect citing dual nationality.
FIFA has ruled that the terms of the Agreement - which state that anybody born in Ulster is entitled to Irish citizenship - no longer apply when procuring players.
This has always been a grey area in Northern Ireland football, where players can carry British and Irish passports.
But, as of yesterday, the FAI can only use players born in the Republic, or those with direct family ties there.
Gibson will not be sanctioned by FIFA for his involvement for the Republic of Ireland in Euro 2008.