LONDON -- The Irish Republican Army's mortar attack on the prime minister's Downing Street office Thursday killed no one, but it did push the possibility of a political breakthrough in the long-running confrontation even further out of sight.
The attack also gave the outlawed organization an invigorating breath of what British officials refer to as "the oxygen of publicity" and put British security forces on notice that they continue to face a resourceful foe.
The dilemma for the government is how much further to tighten the security clamp at the expense of public liberties and political openness.
Prime Minister John Major, a politician who has displayed a taste for ordinary living -- with an appetite for hefty English breakfasts in working-class restaurants and an inclination to walk between his office and Parliament -- will probably be forced to live with tighter security restrictions.
The attack interrupted attempts to arrange talks on the Irish crisis, and it gave politicians in London a taste of the sort of violence that is almost an everyday occurrence in Northern Ireland.
It came in the wake of last week's lackluster annual conference of Sinn Fein, the political wing of the IRA, in Dublin.
Conflicting signals emerged from the conference on the IRA's interest in negotiations, but the mortar shells that flew across Whitehall toward Downing Street ended any doubts on that score.
Hours after the shells shattered the windows of Downing Street offices and sent the British War Cabinet ducking under its meeting table, another blow was delivered to Irish peace prospects.
The British government's yearlong effort to arrange talks on a new form of government for Northern Ireland appeared to founder when unionist leaders came out of their latest meeting with the British secretary for the province, Peter Brooke, to announce that the initiative had "run into the sand."