Northern Ireland is on the brink. But then, Northern Ireland is always on or near the brink. Even after months of nervous peace, in important ways it remains a society living on the edge of a nervous breakdown, a history-drenched province on the brink of the British Union, hanging by its fingertips from the edge of a secular, materialist country that no longer understands its own history.

Our familiarity with confrontation in Northern Ireland could easily dull us to the strangeness of the past few days. A community that prides itself on being law-abiding and loyal to the Crown, and which regarded the Royal Ulster Constabulary as its champion, is currently in revolt against the policy and agents of the Crown and, in particular, the RUC.

Dark-suited, church-going Orangemen find themselves being rebuked by people close to Loyalist paramilitaries of inner-city Belfast. In burning cars, blockading airports, stoning police, and accusing the state of depriving them of their culture, the Unionist rebels are behaving and sounding increasingly like ... well, like republicans.

Early on in the peace process, Conor Cruise O'Brien predicted that it would break down. He mapped out how the breakdown of order would occur, with staged confrontations, escalating violence and rising demands made upon the British Government. What he did not predict was that these things would be initiated by Unionists, rather than Sinn Fein.

At first sight, the timing seems extraordinary, a gormless Orange mistake. Sinn Fein had been in grave difficulty, shut out of the all-party talks yet with no plausible alternative strategy. Though the IRA hadn't returned to violence on the streets of Northern Ireland itself, the killing of a Garda in the republic and the bombs in Britain had sapped support in Dublin and America. Gerry Adams's moving impersonation of Gandhi was ceasing to win him media applause.

And now comes this. If Sinn Fein propagandists had been able to write the plot, they couldn't have organised it better: Catholic families scared out of their houses by loyalists, just like in the Sixties; confrontations between Orangemen and the police; Major urged to disown the chief constable of the RUC. Oh, happy day!

Unionists have learned to play the underdog and to use language that is listened to by liberal opinion-formers, to speak of violations of their civil rights and of the threat to their identity. As with republicans, moderate Unionists have become adept at pointing, half-warning, half-threatening, to the gunmen in the shadows.

Whether this does them any good with liberal public opinion remains to be seen. Professor Steve Bruce of Aberdeen University, whose book The Edge of the Union is one of the best studies of Unionism, points out that they have a deep public relations problem: "Ulster Unionists look terribly like the parents of people growing up in the Sixties - bowler hats, dark suits, stuffy, church-going."

The seriousness of their religious convictions is a problem for the British, too: "We don't much like religion and we are not actually too keen on people who take it seriously. Religion in Britain means Derek Nimmo in All Gas and Gaiters; it's about being nice to people," says Bruce. But, for Ian Paisley, "His God is a jealous god and his God tells him that the Republic is a conspiracy against the last outpost of the true Gospel." All of which provides a barrier between a certain kind of Unionism and secular Britain that PR will never breach.

Many Unionists would respond that the religious fervour and bigotry of Catholic Ireland is as deep-rooted - just much better hidden. And it is true that republican hardliners learnt the language of modern politics far earlier than the Unionist leadership. Many Unionists still tend to wear their bigotry (quite literally) on their sleeves.

How can we reconcile what seem like two opposing arguments about Unionism - that it is helping Sinn Fein by turning to confrontation?, and that it is learning from the republicans? The answer, I think, is simple and bleak: the Unionists are behaving like losers. Their claim to be an endangered and minority species is only partly PR; it is also deeply felt.

And for good reasons, Professor Bruce says, "One doesn't have to be a Unionist to describe everything since the suspension of Stormont [in 1972] as series of anti-Unionist actions by the Government." That is a political judgement, of course, not a security one. From the early Seventies, right through to the ceasefire and the Downing Street Declaration, the British state has spent words, money and the blood of British soldiers to defend the majority in Northern Ireland, while, again and again, putting political pressure on that majority.

Over two decades the Unionists have received a series of propositions about power-sharing, assemblies and compromises which they have been reluctant to hear. Their lack of an alternative political strategy has made them the nay-sayers, the immoveable object, of modern Europe.

But this doggedness, this obstinate tenacity, has in turn helped drive them away from the spirit of modern Britain, even while they remain politically part of the UK. The more they struggle, the weaker they become. They have not had the sophistication, to win a political battle with Irish nationalism and British pluralism.

Whenever the political pressure for change grows intense, Unionism turns savagely provocative. It did so after the first attempt to broker a political compromise, the Sunningdale agreement, which was followed by the1974 Ulster workers' strike. Now, as the political process is quietly insisted on by civil servants and ministers, it seems to be happening again.

At a human level, one can sympathise with the alienation of this community, once so arrogantly dominant, now sliding down. The whole world seems against them. Most of it is.

But this overturning of cars and stoning of police is futile. For Unionists, it is peculiarly dangerous. For the more Unionist militancy, the more anger is directed against the state, the weaker will be British sympathy and Britain's desire to help. Unless Unionism realises that political compromise is something to grasp, not something to fear, it will cut itself off from the modern world and make its eventual defeat inevitable. Unionists, the people on the edge of the Union, can still stone their way out of it.