I suspect that the story was used to sell the GFA to the rank and file.
They thought they were fighting and dying for a United Ireland, not a bit more electoral reform.
If it is true, it is not a progressive way to gain political power is it?
Direct Rule came in 1972, the Civil Rights movement in the North of Ireland was all but dead by that stage. British public opinion didn't come into it,
NICRA did not die.
It was wound up because all its aims were achieved, and it became the SDLP.
British public opinion certainly did come into it.
No referendum was needed to know that we were all appalled at what had been going on.
We supported the Civil Rights movements in NI and US.