The ceasefire has brought to a head two decades of competition between the two Protestant leaders, and between two visions of the Protestant future. Mr Molyneaux is a traditional integrationist, much influenced by Enoch Powell's relentless logic. For him, the task of Unionists is to maintain the Union - and that means not getting too far out of step with the powers-that-be in Westminster. Mr Paisley's bottom line is to maintain the integrity of his Protestant people - which is why he is a devolutionist, and why some of his more extreme sympathisers can contemplate a paradoxical doomsday scenario; an independent 'Unionist' Ulster, achieved, if necessary, by force of arms.
Days before the IRA announcement, the two men had signalled how they were likely to play their hands. Mr Paisley warned, provocatively, that government policy was pushing decent Protestant people towards 'a civil war sitation'. Mr Molyneaux said he had been reassured by guidance from Downing Street that there would be no change in Northern Ireland's constitutional position.
There was thus a symbolic quality about the circumstances in which the old pros gave their reactions to the ceasefire. Mr Molyneaux, a slight figure, stood bolt upright before a microphone in Downing Street. His hands were clutched defensively over his crotch. Sir Patrick Mayhew, the Northern Ireland Secretary, hovered protectively behind him.
And where was Mr Paisley? He was caught by television cameras, head back and defiant, alone on some rainswept street corner from which he was forced by the elements to bellow his rejection of the IRA's 'Jesuitical' statement.
This week, as so often in the past, Paisley and his supporters seemed to make the running in the battle for publicity. It is not so much that the Rev Ian Richard Kyle Paisley - founder and minister of the Martyrs Memorial Free Presbyterian Church, Belfast, founder and leader of the Democratic Unionist Party, MP for North Antrim since 1970 - is the uncompromising and, for many, unacceptable face of Unionism. Down the decades the Big Fella has somehow been able to sell himself outside the Province as the only face of Unionism.
This perception is misleading, and it is unfair to Molyneaux - as well as to the growing number of Unionists he represents. Molyneaux is a suburban, middle-class loyalist, a bachelor who lists his hobbies as gardening and listening to classical music. He would certainly not be caught bellowing anti-papist abuse on street corners. He prefers to talk quietly to influential figures, preferably in the corridors of Westminster or Whitehall - which is why a majority of Unionists vote for his party and not Paisley's.
Mr Molyneaux and his constituency would wish him to be judged as an operator, not an inner-city, agitator. And, as an operator, he must be doing something right. After all, his Unionist Party is now far larger, better organised and more successful at the ballot box than Mr Paisley's party, which broke away from the officials 23 years ago. Yet when Molyneaux became leader in 1979, his party was in seemingly inexorable decline. Under his superficially lacklustre guidance, its electoral support has grown steadily, to the exasperation of Mr Paisley.
To understand this success - and the intense, though intellectually barren, competition between the two Unionist parties - it is necessary to look at how the once- monolithic Loyalist movement has splintered since the Troubles began in the late Sixties.
Unionism at that time dominated a discriminatory system of government. The Unionist political machine was led by grandees such as James Chichester-Clark (Lord Moyola) and the late Brian Faulkner (Lord Faulkner), the last two prime ministers of Northern Ireland. It crossed class lines to embrace Protestant professionals and manual workers who - as a result of systematic corruption - had a near-monopoly of decent public housing and of prestigious jobs in the shipyards and heavy industry generally.
When the civil rights movement challenged the Unionist ascendency, the traditional elite was inclined to compromise. Unionism's new brutalists were not. They had no time for their effete old aristocrats, who, in turn, had no desire to participate in the increasingly thuggish political arena of the Seventies and Eighties. They simply withdrew from politics and have stayed withdrawn.
The official Unionist Party, as a result, is now led by uninspiring though efficient members of the lower middle class. But it has an enviable constituency among the growing number of respectable suburban Protestants - who have done surprisingly well these past two decades. Their quality of life is good and violence has been something read about, not experienced. They have no visceral fear or hatred of Catholics and they are sharp enough to know that their standard of living depends on subsidies from the rest of the UK. Such people do not demean themselves - or endanger their families - by entering politics. They simply leave things to Mr Molyneaux.
As for the once proud, self-disciplined Protestant working class - when the Unionist split occurred, Ian Paisley's Democratic Unionists inherited most of them. Unfortunately for him, they are a declining and demoralised band. As elsewhere in the United Kingdom, the shipyards and factories are running down or being automated. Those blue-collar jobs which do remain have, increasingly, to be shared with Catholics. Job discrimination still exists, but debilitating unemployment has ceased to be an exclusively Catholic experience.
It is the inner-city Protestant working class that has borne the brunt of IRA violence. For these people the quality of life has declined dramatically. They vote Paisley, but without enthusiasm because they see him as a man given to bluster and eventual retreat. Many of their natural leaders - the sort of men who would have been shop stewards a generation ago - are working on the mainland or in Europe. Others flirt with the paramilitaries.
It is hard to see how either Molyneaux or Paisley can pull together the two increasingly divergent Unionist traditions which they have so recklessly encouraged. At this crucial moment, Unionism appears splintered beyond repair and lacking in creative leadership. Yet behind the scenes must surely be potential leaders from a new generation who may be tempted out of obscurity by the chance to help forge a peaceful future. If not, the prospects for Unionism are bleak indeed.