Bertie Ahern is one of the main reasons why Brian Cowen is Taoiseach today. Shortly after he was re-elected in 2007, Bertie took the highly unusual step of going on RTE and publicly naming Biffo as his successor.
Although other leadership rivals such as Micheal Martin and Dermot Ahern were privately furious, this helped to ensure that Cowen became leader of Fianna Fail without a contest less than a year later.
So it's a bit rich for Bertie to turn around now and put the boot into a man who might not even have got the job without his full blessing.
True, the ex-Taoiseach has a point when he criticises Cowen's dire communications skills and failure to prevent the EU/IMF bailout. Given his own role in creating our economic disaster, however, the public is in no mood to take lectures from Bertie Ahern -- which is why he'd be well advised to stick his head back in the cupboard before he does his long-term reputation even more damage.
The split between Bertie and Brian has been coming for a long time. In an interview with the Herald to plug his autobiography back in 2009, Ahern hinted that he was already beginning to regret his decision.
"Brian has been unlucky and he's a very bright guy, but I don't think it's any secret that his work ethic wouldn't be the same as mine," he lamented. "I thought his sharp brain and his oratory would balance that out. If Brian was in the room now he'd have you in stitches laughing, but that side of his personality just isn't coming across."
Now Bertie has taken his public disillusionment to a whole new level. Speaking to the same newspaper who persuaded him to do that infamous television advert, he accuses Cowen of failing to handle the media properly and keeping vital information secret from the financial markets.
He also hints that if he hadn't been forced out of office himself, his vast experience would have saved us from the worst of the recession.
As usual with Bertie, the truth is a bit more complicated than that.
While it's true that he spoke to journalists much more often than his grumpy successor, he often left us scratching our heads over what exactly he had meant to say.
And as last year's devastating banking reports showed, many of the key policy decisions that caused the economy to overheat were taken while he was sitting in the Taoiseach's office.
It is just not good enough for Bertie to protest that nobody ever told him there was trouble brewing in the country's biggest financial institutions.
As leader of the Government, it was up to him to demand regular reports from the regulator's office and subject them to proper scrutiny.
Even if you absolve him of blame for the banking scandals, it is beyond dispute that he created our massive budget deficit by cutting taxes and raising public spending to completely unsustainable levels.
Instead of showing even the slightest hint of remorse for his own blunders, however, Bertie has broken one of the golden rules for all ex-Taoisigh.
No matter how bad the people who come after you are, having a go at them in public will only make you look like a bitter old has-been who can't adapt to life after power.
It's just another reason why he is completely unsuited to be the next President of Ireland -- and if he has any sense, he will stop dropping silly hints and admit that he has given up all hope of running for the Aras this year.
It is worth noting that no matter how bad things have got for Cowen, he has never been anything less than gracious about the man who put him where he is today.
When Bertie announced his retirement from the Dail last week, the Taoiseach claimed that "his fellow countrymen and women will always hold him in high esteem".
To put it politely, that is stretching the truth a bit -- but it was still the correct and decent thing to say under the circumstances.
The only thing the Irish people want to hear from Bertie Ahern right now is the single word 'Sorry'.
If that simple apology is still too much for him to stomach, he would be better off saying nothing at all.