Is Sinn Fein edging towards a working relationship with the new Police Service of Northern Ireland? I use the words "relationship with" rather than "full support for" because the latter will happen when the former is established, writes Mary Holland.
The question is raised not only by the recent terrible violence in Belfast but also by yesterday's mood in the House of Commons. This was sombre,overshadowed not only by the murder of 19- year-old Gerard Larnon but by his mother's heroic plea that there should be no retaliation.
Tony Blair's replies to questions as to whether "more rigorous" standards were to be applied to paramilitary ceasefires sounded more like an appeal to both sides to take what steps they could to revive confidence in the peace process. He was resolute in his defence of the Belfast Agreement as offering the best - perhaps the only - hope of a lasting peace.
Today's headlines will almost certainly focus on recrimination. Anti-agreement unionists will be outraged that John Reid's statement does not go far enough in excoriating the republican movement. Sinn Féin will say it is almost surreal for British government ministers to be talking about the need for the IRA to prove its commitment to the peace process at a time when, to quote Gerry Adams, the UDA is engaged in a "killing spree" directed at Catholics.
As always with the peace process, it is necessary to look beyond the shouts of "crisis!" to deeper changes which are taking place. One of these is a growing acceptance, even among Sinn Féin supporters, that the only way to bring peace and a sense of security to the most dangerous interface areas is through a police force which is able to work with community leaders on both sides of the divide.
To some extent this is already happening. We know that the violence of recent weeks could have been a great deal worse but for the efforts of Gerry Kelly and other Sinn Féin leaders to calm the situation and to argue against demands that the IRA should retaliate in kind. Privately at least, senior officers in the PSNI acknowledge that this is the case.
Alex Maskey, the Sinn Féin Lord Mayor of Belfast, probably spoke for everybody earlier this week when he said, "There is no more urgent task than restoring calm to the city". The violence of the past couple of weeks has brought home that people are desperate for reassurance that there will be no return to the bad old days.
Gerry Kelly, in an article in this newspaper on Monday, rehearsed the reasons for Sinn Féin's continuing objections to the Police Service of Northern Ireland.
He argued that the British government had failed to implement a number of important elements in the Patten Report on numbers, the oath on Human Rights and so on. Many nationalists, however, believe that serious efforts are being made to create a genuinely new and impartial police service.
Just two days ago, the High Court in Belfast endorsed the policy of recruiting 50-50 Catholics and Protestants, even when this clearly involved positive discrimination in favour of nationalist applicants. There has been other important evidence of change - the tenacity of the Police Ombudsman's office in investigating Omagh, an inclusive policing board which has helped to manage change, the fact that there are young Catholics who now see the police service as a career choice.
Changing the culture of a police force takes time, and not only in Northern Ireland. Prejudices about race and women are as deep-rooted as tribal bigotry, but dealing with all these has to be a part of the process of moving forward which Sinn Féin claims it is committed to embrace. The party has already taken brave and important steps to demonstrate this commitment - and will, sooner or later, have to deal with the policing question.
There are important political implications as far as the peace process is concerned. It is hard to think of any move - short perhaps of the public disbandment of the IRA - which would do as much to bolster the confidence of the moderate unionist community as Sinn Féin taking its seats on the policing board.
These moderates are the UUP supporters who are appalled by what they see as the rise of a "mafia society", controlled by paramilitary thugs on both sides, and who have lost faith in the Belfast Agreement as a result. The matter is one of some urgency. It is still on the cards, provided the political institutions survive, that responsibility for security could be returned to the Executive in Belfast next year. That will only happen if Sinn Féin decides to participate in the policing board.
It may be that the Executive won't survive. Martin McGuinness has said he believes David Trimble has already decided that he does not want to face into next year's Assembly elections on the record of having sat in government with Sinn Féin. He chided the UUP leader for his failure to embrace the agreement and then added, philosophically, "but we have to work with him and in my opinion he's the best we've got". If this is the case, and if Sinn Féin wants to help David Trimble, it provides another good reason for the party to reconsider its attitude to the Police Service of Northern Ireland.