The resignation of Longstone over the breakdown in her relationship with Parata may be enough to warrant a major reshuffle and a new Education Minister as well.
Before he does that Key will have to assess how much of the recurring problems in Education (class sizes, Christchurch, Novopay) were the Ministry of Education's fault and how much was down to Parata's own inexperience.
Inexperience of itself is not a problem. Key took a risk with in giving Paula Bennett the hugely important Social Development portfolio and she hasn't let him down.
Her took a risk with Parata as well, a former high-ranking public servant turned consultant and it has been a different story.
Blame for the class size debacle which forced a backdown on a major Budget announcement was as much the fault of the whole cabinet was it was Parata's but she must take responsibility.
Parata was let down by the ministry over its approach to restructuring but Parata accepted their advice.
Craig Foss as Associate Education Minister is responsible for the Novopay pay system debacle but people blame Parata anyway.
Even when a problem has not been of her making, she is responsible, she is blamed.
She and Lesley Longstone began their respective roles as Secretary and Minister at about the same time, Longstone new to the New Zealand education system, Parata new to the pressures of a huge portfolio.
The relationship between a chief executive and minister is like an arranged marriage. They didn't choose each other and they have to make to work. Without it nothing else is possible.
Parata lost confidence in Longstone. But it may be that the public has lost confidence in Parata.