Gladys Berejiklian resigned on Friday, proclaiming her innocence but saying ICAC left her little choice but to resign her job and her seat.
On Sunday, Transport Minister Andrew Constance said he was resigning, to run for federal parliament.
Yesterday, John Barilaro, deputy premier and National Party Leader, added his name to the list.
He cited a range of personal reasons - including a forthcoming Federal Court defamation case - for quitting state politics, triggering a third by-election in a fixed, four-year system where the next general election is almost 18 months away.
In a 25-minute media conference yesterday, Mr Barilaro referred to the events of September last year, when he took a month's "mental health leave" after a particularly volatile political fortnight in which the Nationals clashed with the Liberals over koala policy and the deputy premier threatened - not for the first time - to blow up the coalition.
VIDEO of press conference here
The Nationals, back to the days when they were the Country Party, have always been a burr under the Liberal saddle, but Mr Barilaro - like his federal counterpart Barnaby Joyce - had made it an art-form.
Some in the joint party room may be unlikely to shed tears over his departure.
Some may also wonder why Mr Barilaro thought defamation action was the best way to deal with political comedian Jordan Shanks, known to his 500,000 YouTube subscribers as "Friendlyjordies". Shanks' diatribes against "Bruz" - as he calls Barilaro - are undoubtedly robust, but so was Max Gillies in his era.
The recent travails of federal MP Christian Porter - from Attorney-General to backbencher after taking the ABC to court - shows how private defamation actions by MPs can sometimes end.
Mr Barilaro's Federal Court case, lodged in May, was already closely watched, and by mid-July Mr Shanks had reportedly raised more than $1 million to defend himself, much of it crowd-sourced from some 24,000 supporters.
Whatever happens from here, state Labor led by Chris Minns and Prue Car have been given a gift horse.
Liberals Rob Stokes and Dominic Perrottet are confirmed contenders for the premier's job, while Melinda Pavey and Paul Toole are front-runners in the National Party.
And Ms Berejiklian - if she clears the ICAC - is already being urged to take on Independent Zali Steggall.
