This is an excellent piece on the current situation and puts the current crisis in a decent historical perspective:
Before there even was an Ireland, there were Irish government bonds. Indeed, the willingness of U.S. investors to take a punt on a
state that didn’t yet exist was one of the things that made Irish independence possible.
In January 1920, Irish rebels started to sell bonds in the U.S. to fund their war with the British government. The bonds were to become repayable after an independent Irish state had received international recognition, and they were repaid.