In terms of legitimizing the blunt political instruments and ruthless tactics employed by the IRA and Sinn Fein, then yes, I suppose you could say that their strategy has-in large measure-succeeded.
On the other hand, the campaign of terror conducted by the Provos has only undermined the cause of constitutional nationalism.
In terms of ensuring the protection of the civil rights of Catholics living in N. Ireland, and advancing their chief purported goal, i.e. a united republic, the IRA has been a miserable, unmitigated failure.
I don't view this as a tactical retreat by the British government, even though their choice to release a prominent convict from the republican side of this conflict elicited howls of outrage from Loyalists.
I do agree that this decision is intertwined-to a substantial degree-with the massacres that unfolded on the Tube several weeks ago.
After the Omagh atrocity and the September 11th attacks-one of the consequences of that massacre being an immediate cessation of funds flowing into the coffers of the IRA from the United States-I don't believe that Sinn Fein could be seen as even tacitly endorsing terrorism as a legitimate political tactic.
The mass homicide perpetrated by Islamic fascists on London mass transit merely crystallized a decision that Sinn Fein had already arrived at several years ago.
I wholeheartedly agree that their promises aren't worth the paper they're written on, but I do believe that-under duress-they've agreed to halt the terrorist attacks.
At least, those directed specifically against their historical enemies.