@ossobuco,
Hi Osso,
In Holland orange is the colour of our royal family. The Northern Irish, Protestant Orangists are related to our royalist Orangism (William of Orange and all that).
But unlike red, orange doesnt seem to signify anything stable across borders, politically speaking -- though the sudden increase of political movements in different countries adopting the colour as its banner made me intrigued enough to start a whole thread about it two years ago:
Orange is the new black - in politics?
A couple of interesting examples in there beyond the few I brought in my opening post.
From what I remember, two suggestions that floated from the list was that, 1) it was used primarily by groups that opposed the status quo, a colour of rebellion, but 2) was used as a more post-modern alternative to the militant, revolutionary red that's so closely associated with socialism and communism.
Resistance without the rigid ideology, maybe; a colour perhaps chosen as a flexible alternative that suggested rebellion without locking you into a particular kind of tradition or ideology.
All just speculation of course... (and the Dutch example obviously doesnt fit with that).