Will the government reach its target of 200 city academies by 2010? The wrangling over the Education Bill has already exposed key flaws in the plan for these "independent" state schools, but a more lethal threat has now emerged in the form of legal challenges by parents who don't want them in their communities.
There are several of these court cases and underlying the technicalities of all of them is a simple question: should parents and pupils in academies be afforded the same rights as those in ordinary state schools?
Academies allow for barely any elected parental representation on their governing bodies. Once the sponsors have handed over their paltry contribution - in some cases as little as a few hundred thousand pounds in return for a £25m-plus chunk of state assets - the school is theirs for keeps.
The body of law that protects consumers of ordinary state education doesn't apply to them. Instead, the sponsors get to choose which bits they want to import into their funding agreements - the confidential commercial agreements they sign with the Department for Education and Skills (DfES).
Parents and children could thus become vulnerable on issues such as special needs, exclusions and admissions simply by virtue of the sponsors' wishes. And this could be embarrassing for a government which claims that it is empowering parents.
Early indications are that the first few legal challenges, in Islington, Merton and the Isle of Sheppey - primarily against the closure of schools on the grounds that parents are not being told what their rights will be in the replacement academies - are forcing the City Academies Unit at the DfES to rethink the content of the funding agreements, bringing them more into line with arrangements for maintained schools.
But the long-term effect of these challenges could be more profound. Will putative sponsors still be interested if the much-heralded independence proves to be illusory? Will they want to face well-organised opposition from parents, especially if they are private sector firms with local interests?
Local anti-academy groups are already networking through internet forums, and the legal challenges - led by Matrix Chambers - are being closely followed by interested parents, governors and teachers around the country.
With 27 academies already up and running, the government's response to the challenges has been to dismiss the parents' concerns, on the grounds that the most important human right a child could have is to a good education.
No one would dispute this, or question the idea of ploughing huge sums of money into deprived areas where aspiration and achievement are low - although, interestingly, academies seem to be popping up in places where this isn't quite true, usually in response to funding pressures from the DfES. However, there is never a satisfactory explanation, or any conclusive evidence, to support the idea that schools need to be wholly independent and run exclusively by a sponsor to give a first-class education to every child.
That's probably because it isn't true. And the fact that the government is now arguing that its preferred model for school improvement is the "trust school" - which, for all its faults, is still a maintained school - implies that ministers know that, too.