Sinn Fein constantly demands to be treated like any other party, especially when it comes to access to governments or to discussions about the future of Northern Ireland.
But since it is part of the republican movement, the other part of which is the IRA, it is not like any other party and treating it as such even to encourage it to join the political mainstream is risky political business. Sadly, the events of the week make the point.
Only last weekend senior Government officials met senior representatives of Sinn Fein in circumstances that might have been thought close to ideal, from a republican point of view.
Britain's Tory government and its leader had been overwhelmed; its Secretary of State finally removed from Northern Ireland. Tony Blair and Mo Mowlam were the replacements the republicans had been waiting for, or so they said.
In the Republic, change was going their way. John Bruton was about to be replaced by Bertie Ahern; a Fine Gael-led partnership that included Democratic Left and Proinsias De Rossa by a coalition in which Fianna Fail TDs outnumbered Progressive Democrats by more than 19 to 1.
Since the elections, North and South, Sinn Fein had two MPs, who could if they wished take their places at Westminster; a TD-elect preparing to enter the Dail, and numerous local representatives in the North, including a powerful group on Belfast City Council.
It isn't clear how, in these highly favourable circumstances, the party's representatives had got on with the public officials at their weekend meeting.
But by lunchtime on Monday the world knew what the IRA's contribution to the discussion had been. And it was short, sharp and deadly.
There was no explanation and there could be no excuse for the murder of the two community policemen, David
Johnston and John Graham, in Lurgan. But the repercussions of the deed, like the search for its meaning, spread and will continue to spread like a backwash of confusion.
ACROSS Northern Ireland, thoughts turned to Drumcree, less than four weeks and a dozen miles away; and fear which had been tinged with hope turned to terror and despair.
Mr Blair's anger and resentment were as understandable as the incomprehension of friends of Ireland in the United States.
Bertie Ahern, who had been hoping to start his term with the announcement of an IRA ceasefire, was suddenly unsure about meeting Gerry Adams. He spoke vaguely of having "to hear things" before making up his mind.
Critics detected a deeper uncertainty. The question, some believed, was not just whether or when to talk but what to talk about.
Bruce Arnold, writing in the Irish Independent on Wednesday, could find no logical dialogue for an Adams-Ahern meeting: "On the one side it would consist of incoherence; on the other, of intransigence."
On the same day Denis Coghlan arrived at an equally bleak conclusion in The Irish Times. "Politicians of all parties," he wrote, "sifted through the ashes of the peace process in search of some living embers, but the outlook was grim."
Two writers who looked more closely at the republican movement reported in even more ominous terms in these columns on Thursday.
Mary Holland stressed the urgency of an unequivocal renunciation of violence and warned that, faced with the prospect of an IRA split, Sinn Fein leaders might opt for holding the republican movement together rather than making a traumatic break with old comrades. "This, in essence," she wrote, "is the dilemma that has always faced them and which, sooner or later, they are going to have to confront."
Niall O'Dowd, the publisher of the Irish Voice, agreed and wrote more bluntly of the need to choose between pragmatic politics and the military failure which invariably accompanies the purist vision of the irredentists.
Those who had been involved in discussions with Sinn Fein looked back this week on a series of events during the past 18 months and the still inexplicable behaviour of the IRA. They recalled the day last October on which Warrant Officer James Bradwell was fatally wounded by a bomb at Thiepval Barracks in Lisburn. And senior officials in Dublin felt sure that, whoever was responsible, it wasn't the Provisional IRA.
After all it was only a matter of days since they'd had their latest meeting with Sinn Fein. The series seemed to be going well, there was no excuse for an attack on British army headquarters.
The officials were wrong. And they would have been wrong again if they had applied the same reasoning to an attack, during Christmas week, on policemen who accompanied Nigel Dodds of the Democratic Unionist Party to the intensive care unit of the Royal Children's Hospital on the Falls Road.
There had been a meeting between Sinn Fein and representatives of the Government on that day, December 20th. But at 8.15 pm. two gunmen arrived at the intensive care unit and, within feet of several seriously ill children, opened fire on the policemen.
The Provisional IRA admitted the attack but denied attempting to murder Mr Dodds.
THIS year many commentators had thought a ceasefire likely during the campaign leading to the Westminster elections. April 10th was the date on which several said it would begin. It was the day on which the Provisional IRA chose to shoot Constable Alice Collins in Derry.
It's easier to recount this series of events than to explain the coincidence of political meetings and highly provocative attacks.
David Ervine has argued time and again that the IRA is intent on provoking loyalist paramilitaries to the point where they abandon their ceasefire and return to a full scale campaign of violence.
Such a campaign would be bound to lead to the expulsion of politicians associated with the paramilitaries from the multi-party talks.
But at what cost to the lives and homes of those vulnerable citizens who invariably pay the price of conflict?
There have been rum ours of disagreements within the republican movement, not between Sinn Fein and the IRA but between those who favour political development and those who do not, with the divisions running through both Sinn Fein and the IRA.
What is new this week is that those who are close to the republicans have begun to talk of open disagreement in a way which suggests that it might become a way out of the movement's current predicament.
But not since the 1980s has there been clear evidence of a split. Splits, though greatly feared in the republican movement, have been more frequent than is generally recognised.
Indeed, there is some force in the argument that the republican movement advanced by way of a series of splits between the l920s and the l970s. And a split within the ranks of republicanism, however undesirable, would be preferable to an outbreak of hostilities in which the whole country was embroiled.