Ian Paisley jnr's enforced resignation as a Stormont minister has compounded the sense of unionism's "tectonic plates" shifting. Hardly could the link between the personal and the political be more pronounced.
As Northern Ireland Secretary Shaun Woodward observed, this is a painful moment for the Paisley family. It would be hard to exaggerate the bitter personal blow felt by Ian Paisley snr. The DUP leader and Northern Ireland's First Minister has lost not only a minister but a right hand man and trusted confidant. The former Free Presbyterian moderator's sense of loss will also be accompanied by hurt at seeing his son and would-be parliamentary heir obliged to stand down amid suggestions of "sleaze".
Mr Paisley jnr vigorously denies any wrongdoing in his dealings with and on behalf of North Antrim businessman Seymour Sweeney. The junior minister was evasive when first pressed about their relationship. Questions mushroomed - about Mr Paisley jnr's purchase of a second home from Mr Sweeney; his retention on his father's parliamentary payroll after becoming a minister; and their seemingly high joint rental payments on constituency offices owned by a company of which Mr Paisley jnr's father-in-law appears sole director. As the personal pressure built, so too did the DUP's disquiet on discovering the scale of Mr Paisley jnr's lobbying activities in relation to local land deals and planning issues on the margins of last year's St Andrews negotiations about the future of Northern Ireland.
Media inquiries may have produced no evidence of illegality but, in the end, it seems Mr Paisley jnr's colleagues were unimpressed by his protestation that he had been guilty only of being zealous in pursuit of his constituents' interests. While there is no official confirmation of this, it is understood the junior minister was invited to retire to the backbenches or face suspension by his party.
There was not much comfort in deputy leader Peter Robinson's tribute, concluding that Mr Paisley jnr had "taken the right decision for the right reason" because media coverage about him had become "a distraction" from the work of the powersharing Executive. Mr Paisley jnr acknowledged this in his resignation statement. He vowed not to serve as "a convenient distraction" from the DUP's political message. "What is more, I refuse to be a convenient excuse to attack the position of the leader of my party." However, as he seeks to draw a line under these controversies and rebuild his own political prospects, Mr Paisley jnr will be aware of a general consensus that his resignation has left the leader still-more isolated in a party already impatient for change.