The Government's defeat on the Terrorism Bill changes the political landscape. Before it, Tony Blair was intent on leaving a lasting legacy.
Now he will be lucky to salvage the ruins of his future legislative programme. Labour backbenchers who, previously, could be relied upon to huff and puff but not blow the House down now realise they have power, and many seem determined to use it.
More ominously for Mr Blair, several loyalists who supported the Government on the Terrorism Bill have signalled they will not remain loyal on education. It seems this threat is being taken so seriously that there are reports that the Education Bill will be delayed until spring - to give time for the Prime Minister and Ruth Kelly, the Education Secretary, to assuage MPs' anxieties over the reforms.
So, if I were a Labour backbencher, what would be my central concerns and what questions would I ask the Prime Minister? Trust schools would top my list. I would want to know how a system of trust schools - which, in the words of the white paper, are "independent non-fee-paying state schools" - would raise standards for all. What incentive would these schools have to take their fair share of the poorest, most disadvantaged children when a school's success will be judged on its place in the league tables?
Already evidence is emerging that academies overall are taking fewer of the hardest children to educate. So how will Mr Blair ensure that the success of trust schools is not at the expense of other local community schools?
In answering, he might point to the recommendations on banding in the new white paper. These say schools should offer places to the complete range of abilities to achieve a balanced intake. Research tells us that the most important factor in raising standards for all - the most able, the middle and the least able - is a school with an all-ability intake.
But backbenchers should remain wary because a banding system is only mentioned as a recommendation. It is not clear what force this would have compared with the white paper's assertion that trust schools would "control their own assets and set their own admissions arrangements".
As the Commons select committee report on school admissions argued last year, when there is greater "choice" in admissions it is the schools that select the pupils, rather than the other way around.
If I were a Labour backbencher, I would also want clarification on another question, although asking it might put paid to hopes of a ministerial career: would there be any protection against a future Conservative government reinstating grammar schools in every local authority?
Reinstating grammar schools would surely be easier in a nationwide system of self-governing schools which employ their own staff, on their own terms and conditions, and have freedom over the curriculum. No wonder Conservative MPs cheered as Ms Kelly launched the white paper in the House of Commons and Labour's backbenchers remained silent and stony-faced.
The issue of trust schools is only one of many contradictions in this white paper. Rumour has it that the entire print run of the first version had to be pulped because of arguments between Number 10 and the Department for Education and Skills.
The ideological fault-line at the heart of this third-term Labour administration - whether public services should be contested by a range of private providers or remain locally accountable to the electorate, operating within national regulations - is behind the deep division between modernisers and traditionalists in the Labour party. I suspect this division will be played out during the next few weeks.
As general secretary of the Association of Teachers and Lecturers, I would urge backbenchers to hold their nerve, to continue to question and press for changes to the Education Bill and, in particular, abandon the trust school concept. In ATL's view it is a solution to no known problem.
Dr Mary Bousted is general secretary of the Association of Teachers and Lecturers. Leader 21