Ian Paisley, the raucous agitator who, in his old age, surprised the world by becoming Sinn Fein's genial governmental partner, has been around for so long that Northern Ireland is scarcely imaginable without him.
Yet his Democratic Unionist party has been so damaged by a recent stream of sleaze allegations that the focus in Belfast has now turned to a notion that was previously unthinkable: politics after Paisley.
With his 82nd birthday looming in April, everyone is speculating on just how long Northern Ireland's First Minister will stay in office. He is in belligerent mood – "I have a fairly hard rhinoceros skin," he growled this week – and has declared his intention to stay until 2011. Hardly surprising for a man whose outsize career has been extraordinary as much for its intensity and longevity as for its final surprise twists.
But events are moving rapidly, and few think he will still be here in a year's time.
Until recent months, Mr Paisley clearly saw himself as set for a long and comfortable innings: attaining power had taken him four decades and once in office he was clearly enjoying himself. His lifelong aversion to having anything to do with republicans seemed to melt away as power beckoned, his relationship with Sinn Fein's Martin McGuinness so close and so cordial that they became known as "the Chuckle Brothers".
Mr Paisley's prestige among protestants was so great that a large majority of them accepted, after the initial shock, that the time had come to share power with Sinn Fein.But that prestige has now been dented, not through his actions but those of his son, Ian Paisley Jnr, who has served both as junior minister and as his father's personal helpmate at Stormont.
Junior, as he is known, is not a popular figure, and as a steady drip of sleaze allegations emerged during the past four months, few in his party leapt to his public defence. Many in the ranks, in fact, made little attempt to disguise their pleasure at his problems, regarding his political prominence not due not to any innate ability but to the sponsorship of his powerful father.
The revelations centre on Junior's relationship with a wealthy developer in the North Antrim constituency in which the two Paisleys are based. Some stories concerned possible developments of the Giant's Causeway natural attraction, as well as the purchase of a house from the developer. Then emerged news that Junior was drawing pay not only from his Belfast ministerial job but also as a Westminster researcher for his father. Next came the revelation that the two Paisleys had been paying unusually high rent for political premises.
Although reporters have been zealously investigating Junior's affairs, they have turned up no "smoking gun" of illegality. Nonetheless, his private financial dealings have gone down badly within a party that prides itself on being straitlaced and puritanical. A loss of a recent council by-election which the DUP had expected to win served both as a wake-up call to the party and the last straw for Junior's ministerial career.
He resigned his ministry, though insisting he had done nothing wrong and asserting yesterday that "the Paisley brand" had not been damaged. But he is almost alone in that assessment.
In any case, senior party figures have, in recent months, been gently telling the First Minister that he cannot stay for ever, and should be planning an orderly succession process. Setting a departure date would be a good idea, they have gently suggested, allowing him to depart the stage with grace and dignity.
Mr Paisley has, however, declined to do so since he – and everyone else – knows that this would render him a lame-duck figure.
But he is now more of a figurehead than a dynamo in the government, leaving much of the heavy administrative lifting to Peter Robinson, the Finance minister, and other heads of department. The fact is Mr Paisley has no huge agenda to push through: for him taking power was itself the pinnacle of his achievement and ambitions. So if he leaves it will not disrupt any great plans. The expectation of most – and the hope of practically everyone supportive of the administration – is that Mr Robinson will take over.
The other serious potential contender, Nigel Dodds, shows little appetite for a contest. Mr Robinson has great experience, having been Mr Paisley's deputy for three decades, and ability.
He is also highly supportive of power-sharing, and although he is not one of nature's chucklers, he has worked well with Mr McGuinness and other republican ministers. Hopes are high that a new Robinson-McGuinness team would function well, probably making up in efficiency for anything it may lack in geniality.
Interestingly, Sinn Fein has been a model of restraint, keeping criticism of Junior to an absolute minimum and offering nothing but support to his father. Like everyone else, they are hoping for a smooth transition.
Whenever Mr Paisley goes, the family name will not disappear. His wife is in the House of Lords, Junior wants a Westminster seat and two Paisley daughters are employed at the Assembly. The question now is whether he will deploy his rhinoceros skin to tough it out, or whether he should go soon rather than wait to be pushed.
If he decides to go, May would offer a good moment, since it will bring a landmark investment conference and the first anniversary of the formation of the Paisley-Sinn Fein administration.
He will have time to ponder exactly when the era should end. He will be pondering, too, the role of his son in hastening his departure, and on the ironic biblical ring to the fact that the sins of the son are being visited on the father.