A lot changed last week, but there is more that needs to change. You find the task and the challenge in the words of Nuala Kerr as she spoke so powerfully after the murder of her police constable son, Ronan: "Don't let his death be in vain."
New words were spoken last week; new steps taken. The language of the Sinn Fein leadership changed - deliberately so.
Gerry Adams, Martin McGuinness, Pat Doherty and Gerry Kelly all described the bomb-attack on Ronan Kerr as 'murder'. They would never have used that word to describe an action by the mainstream IRA that took the life of a member of the security forces.
And that choice of language by the republican leadership was about creating distance and difference between the IRA 'war' and the dissident campaigns.
I interviewed Gerry Kelly at the City Hall rally in Belfast, where he spoke of armed struggle as "a last resort". "This is not a last resort situation," he said.
Kelly was part of the IRA 'war' and, according to security assessments, was at one time a member of the army council leadership. He does not hide that past and has spoken publicly of being "proud of it".
But his argument is that things have changed and that Ronan Kerr was part of making that change possible.
Dissidents still see the police as an enemy - Catholic police officers in particular. That is why that bomb was made: the lunchbox device containing high explosives and a tilt switch; the bomb that meant that Ronan Kerr had no chance.
At his funeral, we witnessed more of the change, not just the presence of First Minister Peter Robinson at Requiem Mass, but also that very public show of strength and support given to the Kerr family by the GAA.
This killing changed so much, but it has not changed everything. There is still a violent mindset out there and a war attitude that condemned Ronan Kerr to an appalling death.
"These guys [the dissidents] are just as, if not more, determined to take more life," a PSNI source said.
So, for all that has changed, there is still that threat and that means there could be a bomb under another car, that another attack is being planned, that someone else is being targeted, that the dissident 'wars' are not over.
Adams, McGuinness, Doherty and Kelly have to find a way of getting the dissidents into a room. They have to go beyond saying they are prepared to talk to them - to the point of actually making that happen.
Inside the republican community, Sinn Fein has tens of thousands of votes that support that move away from war and into the peace negotiations. Those people - those thousands of people - have to make this conversation happen. And they can, if they think about it, make it happen.
It is what the former senior police officer Peter Sheridan meant last week when he said: "We need more than condemnation - important though that is."
He also made another important point: that talks with dissidents should not be ruled out.
"If you look for a security response, then the danger is that you expect it to be 100%, which intelligence can't be," he said. There is another question to ask and answer: do we really need the Security Service (MI5) here in that headquarters at Palace Barracks?
In many minds, MI5 still means 'spookery' and war-games. It is a read back into the conflict and the old days.
And it is an excuse that the dissidents use to try to justify their actions; to make the argument that policing has not changed, that the PSNI is the RUC dressed up in another uniform and title, that the British still control policing.
There must be another way of doing intelligence, doing it within the new policing structures. I discussed this at a seminar at Queen's University last week where I was invited to speak by the Committee on the Administration of Justice (CAJ).
The argument I made was that young officers from the nationalist and republican communities are the people who are going to make the real difference - who have the best chance of changing mindsets.
You can see them; see that change. But you cannot see inside MI5, inside that secret world. That intelligence method is the old way, not the new way.
Just think about it. Will the nationalist and republican communities have more confidence in their own young people than they will have in the Security Service?
Are they more likely to speak to and provide information to those young people, to those they know - not just the nationalist and republican communities, but all communities here?
This is the next challenge; to think beyond MI5, to think outside the box, to think what has the best chance of working here.
New policing is not just about implementing the recommendations and reforms of the Patten Report. It should never be about jogging on the spot.
The thinking must always be about what is working and what is not - what might produce better results.
Nuala Kerr gave us all something to think about when she said don't let Ronan's death be in vain.