It is easy to blame the gargantuan size of the government's majority for the failure of the top-up fees rebellion, which finally fizzled out at the report stage of the Higher Education Bill on 31 March. But it is as much to do with the inability of Labour rebels to muster their forces at the right time or, to put the credit elsewhere, with the ability of the whips' office to divide and conquer. Even when there is enough back-bench support to defeat the government, the rebels just don't do it.
Take foundation hospitals. As the Health and Social Care Bill worked its way through the Commons, a grand total of 87 Labour MPs were prepared to vote against it - easily enough to defeat the government. The problem was that they did not all do so together: the biggest rebellion on this subject involved 65 Labour MPs.
Exactly the same happened with top-up fees. Throughout the passage of the bill, a total of 82 MPs voted against - again easily enough to stop the legislation. But the largest single rebellion involved only 72 MPs - which on the second reading reduced the government majority to five.
Six Labour MPs voted against the bill on 31 March who had not done so at the earlier vote in January. But they were more than counterbalanced by 21 MPs who voted against the government in January but who then abstained (18) or voted with the government (three) in March. And then at the third reading, which followed closely on the report stage, four new MPs chose to vote against the measure for the first time, though most Labour rebels then abstained and there was no chance of a government defeat.
There can be perfectly good reasons for the changing composition of a rebellion. Some MPs may be persuaded back into line by government concessions. Others may choose to hold their fire at first, while reserving the right to rebel if they don't feel the concessions are sufficient. Still others are prepared to rebel only when there is no chance of defeating the government - to bark but never to bite.
Yet the end result is that, despite the presence of enough rebels to overturn two flagships of the legislative programme, this government remains undefeated on a whipped vote. No government since Harold Wilson's in 1966-70 has managed that.
Philip Cowley runs www.revolts.co.uk and teaches politics at the University of Nottingham