The new Omagh tragedy highlights the country's political problems, and Cameron's duty to help solve them
It's a "wicked and cowardly act", says the British prime minister. "And a pointless act of terrorism," echoes his new Dublin counterpart. These guys, whoever they may be, are "betraying their community", says Martin McGuinness. Absolutely, echoes his new sort-of Stormont boss, Peter Robinson, "they're Neanderthals". One dead policeman, blown up by a car bomb outside his Omagh home; so many voices from north, south, east and west condemning any hint of a return to random killing.
You can choose to be reassured if you wish. Northern Ireland's grand coalition still functions (with Robinson, not Paisley). In the 13 years since the last, traumatic Omagh bomb signalled a formal end for even the Real IRA, peace has survived, flourished, become normality.
Why, isn't the Queen off to Dublin soon? Didn't Chancellor Osborne dip his hand in our pockets to bail out Ireland's tottering banks? Who on earth wants to see a few demented deniers, with leftover lives to kill, reignite the carnage because they are bored, mad or terminally stupid? There is surely no "continuity" for this soiled brand of republicanism, only oblivion? Globalisation, take it away.
Yet this commonsensical chorus only takes you so far. It clears the bloody detritus of the past; it provides a suitably united response to the murderers who remain; but somehow it still fails to address or secure the foundations of a quite different future.
Nationalism (as chronicled by the Guardian in Catalonia and the Basque country last week) is an itch that can never be quite scratched away. It is the politics of real or supposed deprivation. Those bastards over there – in Madrid, or London – aren't being fair! Only we, ourselves, alone, can provide such fairness. Wreathe that struggle in mists of rhetoric and selective history and there's a potent refrain that declines to die. It may fall silent for a decade or two. But you can't ever be sure that it's gone forever unless other fresh tunes totally drown it out.
So here's the next challenge, beyond simple condemnation, for Westminster, the Dáil and for Stormont. It's been vital for Catholics and Protestants to come together in government, for the polar opposites of the Democratic Unionist party and Sinn Féin to show they can rule in relative amity. This was always the mandatory first stride towards sanity and away from the turmoil of terror. But it was only a first stride – and until something more akin to normal politics takes over, with one lot in and another lot out because the electorate says so, until the essential arguments are all about schools, hospitals, roads and taxes, then the past will never be wholly exorcised.
There's nothing impossible about such progress. Indeed, at local council level, it is part of the existing landscape. But, in a Stormont still defined by religion and mythic decisions, the old talk and old constituencies linger on, lighting fires on mean constituency streets.
PC Ronan Kerr, a young Catholic policeman – his PSNI choice a symbol of reconciliation – died horribly on Saturday. His killing is all about the past (and perhaps a little about the boredom of political stasis as usual). It was wicked to kill him, as No 10 said; but it's also a touch cowardly for those who represent the huge, rational majority not to want to move on as well.
Northern Ireland has lost prominence in the UK affairs; its secretaries of state have small salience and not much to do. Its problems, in Downing Street terms, are labelled "solved". They aren't. Not in terms of pursuing a few mad men, but in terms of driving the whole dynamics of political change. We may praise Messrs Major and Blair, among many others, for what they helped bring to pass in Belfast. But now David Cameron is part of that future, too.
• This article was amended on 4 April 2011. The original version made reference to Ronan Kerr's "RUC choice". In fact, PC Kerr joined the police in May 2010, nine years after the demise of the RUC. This has now been amended