this was a popular referendum - there was quite a large "No" lobby [lead by Sinn Fein/DUP - both 'hate' each other. i'll come back to this]. the good friday agreement was sort of a first steps towards devolution here. the two parties in charge of northern ireland then have since faded into the political wilderness [UUP and SDLP] while the more radical parties of the DUP and Sinn Fein have stepped into that vacuum. both parties are still 100% self-serving, and seem to agree when it comes to ego.
there are still people who think that Sinn Fein should have never agreed to joint government with the DUP [St Andrews Agreement] as this was essentially selling out and forgoing a united ireland. sinn fein being the party that advocates the united ireland stance. now that mainstream republicanism is sitting in a british system of government presiding over a british devolved state, a minority of people are very wound up over it all.
the idea behind the shooting of the two soldiers was for these outcasts to try and get soldiers back on the streets here in n.ireland, an optical justification for their beliefs. it's a vast overreaction on the part of the british government they want that will help to fuel their ideology.
process? yup, i don't know anyone in n.ireland who doesn't want a lasting peace. but 400 years doesn't melt from memory easily.