POLITICAL STRUCTURES: Restoring the suspended institutions of government, and protecting them against future unionist boycott or disruption is a central concern of republicans and nationalists in the "acts of completion" negotiations.
The issue has a bitter history, almost as old as the Belfast Agreement. Mr Peter Mandelson ensured himself enduring nationalist and republican enmity on Friday, February 11th, 2000, when he suspended the Northern Ireland Assembly for the first time.
Just 24 hours before, the then secretary of state had secured the royal assent for the Northern Ireland Act, 2000, giving the British government a power of suspension which the original draftsmen had neglected to incorporate into the 1998 Act that gave effect to the Belfast Agreement.
Sinn Féin and the SDLP railed against this "breach" of the Good Friday accord. Dublin protested equally loudly, finding itself embarrassed to watch the institutions suspended by a unilateral British act after just six weeks, and on the heels of the Republic's earlier agreement to the constitutional change withdrawing Articles 2 and 3 and the territorial claim to Northern Ireland.
A key component of the present negotiations is Sinn Féin's demand for the repeal of the Mandelson legislation.
At first glance this appears to make little sense and to offer republicans no guarantee at all. It might serve as a statement of Mr Blair's good faith and intent but, as Sinn Féin fully understands, no prime minister can bind a successor government.
And Britain would, in any event, retain the sovereign power in all future, unforeseen circumstances.
However, while accepting that there are no guarantees in politics, republican sources think the effect would help stabilise the political process by removing from Mr Trimble's hands the immediately available threat of suspension.
Pressed on possible alternative forms of guarantee, these same sources now dismiss talk of changing the Assembly's cross-community voting rules to permit a minority unionist bloc to sustain the Executive as part of a simple pro-agreement majority. Sinn Féin now seems to share the British government's view that this would open the way to the DUP's proposal for a wholesale renegotiation of the agreement.
On the question of the Mandelson legislation, it seems Mr Blair is prepared to oblige. Again, cue his Belfast speech last October: "We are prepared to do what is necessary to protect the institutions against arbitrary interruption and interference."
But again, too, the caveat: "That means also commitment from others. Unionism to make the institutions secure and stable. Nationalists to act if violence returns." For "nationalists" in this context we must read "SDLP".
On the assumption that the SDLP would never vote to expel them, Mr Trimble wants an independent element in ceasefire monitoring and quid- pro-quo provision of new "exclusion mechanisms" to be deployed against Sinn Féin, should republicans again be deemed in breach of the commitment to peaceful and democratic means.