As we all take in the tragedy of the murder of Constable Ronan Kerr, we should not lose sight of the sincerity and unity with which the leaders of all Northern Ireland's political parties - nationalist, republican and unionist - have spoken.
We think of Constable Kerr with profound respect. Our hearts go out to his mother and family. And to the people of Omagh, for whom this brutal assassination rekindles a deep wound.
And we thank too the police family of Northern Ireland, who today - the gravest risks to each no less - are at work, serving selflessly the community.
The men and women of the PSNI do not see themselves as extraordinary. But in what we ask of them, in the very serious risks they endure each day, we know them as extraordinary.
In his courage and service, Ronan Kerr exemplified that spirit.
His commitment - working for one community, Protestant and Catholic alike - stands in juxtaposition with the deluded and demonic deeds of those who targeted Ronan.
When the Belfast Agreement was signed, we all hoped that the residual threat from terrorism would remain low and gradually decline.
Regrettably, optimism must give way to realism. The threat is not low. Today it is severe. More serious than in nearly 15 years.
Today's terrorists may have little or no community support, but we delude ourselves if we do not recognise that a new generation has grown up, foolishly embracing a new wave of deadly violence.
Excepting national security, responsibility for policing and justice is devolved to Stormont. The Secretary of State recently succeeded in persuading his Treasury colleagues to provide additional resources from the Reserve.
We need to be reassured by the Government that, if Northern Ireland's Chief Constable should require additional support to ensure the ongoing demands of community policing, for the public and for the safety of officers alike, the necessary resources and money will be there. And that these will be made and agreed without delay.
To confront today's threat we must ensure that we not only tackle the existing numbers of terrorists, but also do all we can to stop alienated young people being drawn into this pattern of crime.
Co-operation Ireland is urgently seeking additional financial support for its critical work in this area from the Government.
To ensure we are guided not by optimism, but by realism, the Government must reassure the public that in the provision of police and security resources in Great Britain, the police will have what they need to address this threat level.
And if we are to learn - as the head of MI5 has said - from "the pattern of history", we need to be sure the co-operation between the PSNI and forces in Britain appropriately meets the increased security threat, including timely and comprehensive sharing of information.
Without capability, the threat from terrorists will be contained. Those supplying these criminals must also be brought to justice.
The Government must ensure no one is above the law and cannot exclude anyone involved in the past in the supply of weapons or explosives. Should the PSNI wish to conduct interviews with any foreign nationals currently in Britain, the Government, of course, should immediately help facilitate this.
Many people will have seen the statement made by Constable Kerr's mother on television.
Sunday past was Mother's Day and when so many sons and daughters remembered what their mother's had given for them, Nuala Kerr - in the hours of darkest grief - shared what her precious son meant for her and her family.
She spoke for us all: "We are so proud of Ronan and all he stood for. Don't let his death be in vain." Let us all play our part in answering his mother's plea.