We have been here before. During the H Block protests and the subsequent hunger strike the republican movement made strenuous efforts to establish a right to special status for prisoners convicted of politically motivated acts of violence.
Human rights bodies were called in but the conclusion was that no such legal right existed or could be enforced. It looks like it is the same in the Spads Bill — only complying with the law or reaching political agreement to amend it provides a way forward.
This is a bitter pill for Sinn Fein. Two ministers, Martin McGuinness and Caral Ni Chuilin, are former republican prisoners along with Jennifer McCann, a junior minister. So are three MLAs — Raymond McCartney, Gerry Kelly and Pat Sheehan.
The party is still partly led by the same generation who fought in the IRA during the Troubles and cutting them adrift would be like cutting off an arm. Sinn Fein must do whatever it can to protect the position of ex-prisoners. Without their buy-in we would have endured years more conflict.
Members of other parties concede privately that Paul Kavanagh, the former prisoner who stands to be sacked under the new legislation, is a supporter of the political process. “He is able and he is a steadying influence,” one unionist who knows him conceded.
Sinn Fein's mistake has been to see this all as a matter of immutable rights rather than political deal-making. They could have backed an SDLP amendment which would have limited the Bill's jurisdiction to newly-appointed spads.
They could have moved Mary McArdle, the ex-prisoner who was Ms Ni Chuilin's special adviser, as soon as Ann Travers raised her involvement in her sister's murder. A prompt reaction to the problem, Ann Travers says, might have stopped her seeking legal change.
Those chances are missed but lessons can still be learnt. The principal one is that all rights are ultimately expressions of social and political consensus. They exist as long as there is broad agreement on them, and agreement has to be worked on.
Sacking Mr Kavanagh may be contrary to the spirit of the Good Friday Agreement, as Sinn Fein argues. Yet that doesn't mean his right to be a Spad can be enforced once opinion shifts and new legislation is passed.
Legislation always changes accepted ground rules; that is the whole point of it.