Show leadership and walk the talk, Martin
Adams and McGuinness have urged republicans to pass information about Ronan Kerr's killers to police. Now they must lead by example, says Malachi O'Doherty
It is hard for Sinn Fein leaders to say plainly that those who can help catch the dissidents should take their evidence to the police. They have, however, come as close to stating that baldly as they have ever done.
In the past, their reactions to the dissidents have amounted to a call that they should come forward and explain themselves - as if the objective was to get them into talks, rather than into jail.
Martin McGuinness has been better at the condemnatory language than the prescriptive. So the dissidents are "enemies" and "traitors" who should remove themselves from the scene.
We can't doubt that he is bloody furious with them - and it is hardly surprising.
The dissidents are using the strategy that worked for past generations of the IRA.
In January 1919, Dan Breen's men shot dead two RIC officers and started a guerilla war that would lead to the collapse of the British state in Ireland.
When Irish people were unwilling to join the police, or be seen in their company, and huge numbers discarded their uniforms for their own safety, then Ireland became a problem for the Army straggling back from Europe - a political problem to be resolved urgently.
In the 1970s and 1980s, the IRA attacks on the RUC helped deepen the rift between the police and the Catholic people. Few Catholics would join and the reality of a Protestant force made reform an essential part of political settlement.
The aim had been to make Northern Ireland ungovernable and to put Irish unity on the table. That bit didn't work.
Similarly, when the British tried to ease pressure on the police and replace the totally Protestant 'B' Specials in 1970, they created a local regiment - the Ulster Defence Regiment - and urged Catholics to join.
The IRA bombed those Catholics in their cars and shot them and soon the UDR was almost exclusively Protestant and that brick in the new dispensation being attempted was invalidated.
Gerry Adams and Martin McGuinness know that history better than most of us.
They therefore understand what the dissidents hope to achieve and have a sense of how realistic their target is.
If Catholics shrink back from joining the PSNI, in the context of the abolition of the 50:50 rule securing places for them, then Sinn Fein could find itself in partnership in Government with an almost exclusively Protestant police force. The party could not live with that. All the reforms of policing, the Police Ombudsman, the Policing Board and all the human rights legislation would not cover the indignity of Catholic republicans being pursued by Protestant police officers and of suspect, but often innocent, young Catholics being arrested, searched and questioned.
McGuinness knows that policing is the loose brick in the peace wall because his own tradition in republicanism trained him to loosen that brick in the hopes that the wall would tumble.
That being the case, he has no choice but to defend the police and the Catholics who have joined and who might join. In doing so, he is defending his own position and his political legacy.
If we revert to Protestant policing, everything he has done will have been in vain - a thought that should, perhaps, have occurred to Owen Paterson before he scrapped the 50:50 rule.
The collapse of Catholic policing must be McGuinness's worst nightmare.
It would amount to his own peace accord with the DUP being undermined by the same methods which he used himself against the old Stormont and direct rule.
There would be an elegant, karmic symmetry to it that one might relish if it wasn't such an appalling prospect for the rest of us, too.
So Sinn fein must now signal to the Catholic community, and to other republicans, that touting is no longer a sin, or a crime. They must encourage a flow of information to the police about the dissidents and help put them out of business. And they must take a lead in that.
This is the hard part for republicans. Michael Collins, in 1921, stormed his former comrades holed up in the Four Courts and blew them to oblivion.
History is letting the Provos off lightly in not plunging them into their own civil war.
On balance, McGuinness must surely see that this is not as hard as facing into failure would be.
He is already being told that he is a hypocrite for condemning the murder of Ronan Kerr, having endorsed the murders of 301 other police officers, a policewoman shot in the back outside Derry courthouse, men shot on their doorsteps, coming from church, visiting hospitals.
Hard, too, will be the challenge of preserving that memory as honorable while telling those who would use the same methods today that they are enemies and traitors.
Today, Martin McGuinness says that the police must win. Now he must tell the dissidents that he was in the wrong, too; that the best evidence that they can't win is that the Provos didn't win either.
And he must sit down with Chief Constable Matt Baggott - if he hasn't done so already - and tell him everything he knows that might help him nail the old diehards.