AFTER yesterday's outline of the forthcoming Northern elections and talks, there will inevitably be a period in which both unionists and republicans will pick holes in the structure and cast about for reasons why they should not participate.

Both traditions are sharply challenged by the concepts unveiled. Both are faced with the requirement to make substantial concessions.

The first test faces Sinn Fein and is crucial: the requirement that the IRA reinstate its ceasefire if the party is to be permitted to participate in the negotiations. This has, been, and will continue to be, defined by Sinn Fein as a precondition, and indeed it plainly is.

"Since it is clearly not to be expected that the two governments will change this requirement, it becomes a matter for the IRA to decide whether to relieve Sinn Fein of this precondition. That will certainly be considered on the basis of the total package.

There are two stumbling blocks here. One is that the timing is now crucial: the republican leadership will have to consider whether a restoration of the ceasefire before participation in the election would benefit them electorally, or otherwise.

They will also consider whether postponing a ceasefire decision right up to the eve of the June 10th talks date would simply give the unionists more excuses for refusing to engage with Sinn Fein.

They may play the brinkmanship game of making no announcement at all, on the basis that negotiations for a settlement without Sinn Fein participation would be meaningless (the SDLP would also remain outside).

But the governments clearly will not relent on the ceasefire requirement and they will have the powerful backing of American and international opinion, so it is realistically unprofitable to pursue that stand off. The question, therefore, returns to timing.

The second stumbling block making an IRA decision very difficult is that the ground rules for the all party negotiations, as published yesterday, have some glaring and absolutely vital omissions.

No detailed procedural rules are set out. No sample agenda is listed. There is no methodology for adjudicating when a "sufficient consensus" has been reached to deem a decision as having been taken.

All of these operational matters must be agreed by the participants. They can talk to the governments about them in advance of June 10th, and they can talk to each other if they wish (but certain fixed positions already assumed will prevent such comprehensive contacts).

However, the burden of deciding on these key operational matters, it appears, will actually fall on the opening plenary session of the negotiations themselves.

The spirit in which agreement is sought on these issues, and the actual resolution of them (if possible) will determine whether or not the entire negotiations are to be "real and substantial", as Sinn Fein demands.

So the IRA will be required, apparently, to make a formal concession (sealing the informal ceasefire which now seems to prevail) in advance of the first crucial test of the negotiations.

There are, however, other substantial inducements to Sinn Fein and SDLP participation. Yesterday's outline made it as crystal clear as could be expected that the forum will be strictly uncoupled from the negotiations and will have little or no power, other than whatever the negotiating teams, by consensus, cede to it.

It will, in effect, operate much as the Forum for Peace and Reconciliation did in Dublin; taking submissions far and wide among the community, and contributing a sense of public ownership of the whole process. The nationalists had no problem participating in such an exercise in Dublin: the unionists will continue to be unhappy with the concept.

The unionists will play their own form of brinkmanship throughout the election campaign and in the run up to the talks. They will attempt to force a resolution of the decommissioning issue at or before the opening of negotiations, rather than accept - as suggested in yesterday's documents - that it should begin to be addressed at the start of negotiations.

The DUP will not sit in the same room as Sinn Fein (assuming Sinn Fein participation). They may sit in an ante room, with emissaries going to and fro. But this raises the question as to whether such an arrangement can actually be defined as all party negotiations.

Predictably, all of these thorny procedural issues will be left hanging in the air until the last moment. An early IRA renewal of ceasefire, and a firm espousal by Sinn Fein of the Mitchell principles, would call the unionist bluff and cut through a lot of the artificial pretalks distractions and manoeuvring.

But republicans may be unable to resist the ploy of demanding more precise details and guarantees on the outstanding procedural areas before committing themselves.

A key aspect of yesterday's material, however, is the fact that the Framework Documents, the Downing Street Declaration and the concepts of consensus and consent are very much back on the active agenda.

It is already evident that all the parties will await the processing of the legislation through the British parliament before seriously addressing the hard decisions which they must make.

The will then very rapidly have to decide whether to commit themselves on some of these vital points before engaging in the election campaign. Their showing in that contest could depend to a large extent on how constructive a position they seem to be adopting.

The British strategy is heavily dependent, obviously, on getting the all party negotiation process under way. There is a heavy reliance on the expectation that the negotiations will create their own dynamic; that, once begun, each of the participants will have too much to lose by unilaterally "pulling the plug".

The options are too varied and multiple to allow firm predictions at this stage. Sinn Fein could decide to participate in the forum (as it may even without a renewed IRA ceasefire) and wait for the negotiating parties and the governments to relent and call them in.

But that would fly in the face of their incessant demand for the all party negotiations and would be tantamount to deliberately postponing the start of real talks. Their loss of credibility could be massive.

The unionists could try a similar ploy, as they would prefer the forum to be the real focus, rather than the negotiations. Each will be watching the other for the first move in this complex situation.

But the clock is ticking, and the real danger is that if the jockeying for position is carried on too long, the deadline for the talks could creep up without any absolute commitment by the main players to the decisive settlement process which the community at large has aspired to for so long.