Originally Posted by chodadog

There's a strong bond between catholics in Ireland and Scotland to begin with. Too many links to ignore. But Celtic FC has its roots in immigrant catholics from Ireland. Which is true of much of the catholic population of Glasgow too. So naturally, they identify with their Irish heritage and in turn with Irish nationalism. Many Scottish born people with Irish links went on to become great Irish patriots. James Connolly would probably be the best example.

And the issue of sectarianism can't be ignored either. Something like 5% of Celtic supporters are catholic and it's a similar number for catholics that support Rangers. You certainly won't ever see a Union Jack being waved around by a Celtic fan, nor will you see the tri-colour being waved by anyone in blue. Wearing a Celtic FC shirt or a Rangers shirt in Belfast is a very tribal thing. You wouldn't walk down the Shankhill in a Celtic Jersey and likewise, you'd be a mad man to walk down the Springfield Road wearing a Rangers jersey.