What is this idiotic idea about Ireland rejoining the Commonwealth?

In today's Irish Times is a snarky and condescending editorial apparently responding to some political movement for the Republic of Ireland to rejoin the British Commonwealth. Although I try to follow Irish politics fairly closely, this is the first I've heard that such an idea was even being considered. Needless to say, I was appalled. Whose idea is this? Surely it doesn't have much political traction, especially since Ireland is a member of the European Union and the U.K. is not. I'll research the matter a bit myself, but I'd appreciate your opinions on the matter.