Publishers' deadlines operate under Murphy's Law. Henry McDonald completed this valuable biography before the power-sharing executive was dissolved. That leaves the author, like his subject, with the uncomfortable appearance of having preferred hope to experience.
In this, they have been famous - if not always wise - company. The British and Irish governments, Bill Clinton and the massed media of Britain and the world have floated through the past couple of years in a cloud of euphoria. Frequent disappointment has been dispersed by perceived "seismic shifts" in IRA attitudes. Eyes have been averted from continuing loyalist and republican punishment-beating and knee-capping. The growing scepticism of many non-political unionists has been ignored, in the hope that it will go away.
Everything has changed, yet nothing has changed. The goodwill that followed the events of Good Friday, 1998, has eroded. Distrust among unionists, nationalists and the two governments derives from a growing perception that the agreement so painfully constructed has fatal flaws. Yet again, we learn an old political lesson: a referendum settles nothing.
The most useful part of this book is its account of David Trimble's early political manoeuvring. As a key member of Vanguard, a unionist breakaway group, he bore heavy responsibility for bringing down the previous power-sharing executive in 1974, an achievement in which he gloried. Yet that pioneering executive had given Ulster a real chance, perhaps its last, of a sane settlement. Trimble was then too close for a democratic politician to the paramilitary bullyboys who forced people to join the Ulster Workers' Council strike. He gave them political and legal advice, and edited the strike bulletin.
Now, as the leader of Northern Ireland's largest party, Trimble faces the task he made impossible for others. Successive Unionist leaders, before reaching power, have thwarted the reforming efforts of their predecessors. Brian Faulkner, the chief executive in 1974, helped to undermine Terence O'Neill, the first reasonably liberal Unionist leader, just as Trimble joined those who undermined Faulkner. Young men who do not learn from history find it rearing up to frustrate their own efforts. Several ambitious men are snapping at Trimble's heels.
One criticism of McDonald's book is that his judgements of the Troubles before his own time as a reporter are often cavalier. To take an egregious example, the name of O'Neill - one of only half a dozen significant figures in the modern history of Northern Ireland - is spelt with one "l" in both the text and the index. I hope it is not pedantic to suggest that a writer who spelt Attlee with one "t" might not be the most reliable guide to British postwar politics.
This misspelling would scarcely matter if it were not compounded by a simplistic view of events in the 1960s. Is it really right to say that Vanguard "had become a nursery for the new unionist and loyalist talent that had been held back in the atrophying years of Unionist Party monopoly rule"? As the book records, Vanguard "marshals" wore paramilitary uniforms and crash helmets, and gangs of young Protestant thugs added menace to their rallies. There were all manner of things wrong with Unionist governments, but it is difficult to argue that the party has improved in the wilderness.
Trimble is a politician often tripped up by his own ingenuity. Throughout the Good Friday negotiations, he concentrated too much on fighting the last battle to avoid too elaborate all-Ireland institutions. That was necessary to him, but not enough. Success on a different issue would have given him more credit with sensible citizens, as distinct from his party elite.
During that long Good Friday, Trimble ought to have insisted on some equivalence between the two issues for which it is the British government, not local politicians, that bears unique responsibility: the release of republican and loyalist prisoners, and the destruction of private arsenals. The logic of this equation is compelling. If convicted murderers have turned their backs on violence, they do not need weapons. The truth, as the continued paramilitary punishments and sentences of exile make hatefully clear, is that the thugs need weapons to maintain their control of the Protestant and Catholic ghettoes. Society is in danger of condemning working-class people, Protestant and Catholic, in the most difficult parts of Ulster, to rule by bullyboys, as a price of buying peace for the local middle classes and English cities.
On this issue, Trimble failed to see that assurances from Downing Street were not bankable. He allowed a different equivalence to be established: between weapons decommissioning - what a ludicrous circumlocution - and a devolved administration. He has been struggling ever since, and so has Tony Blair.
John Cole is a former political editor of the BBC