If you listen to the Liberal Democrats, the changes in the NHS bill have been wrought by the influence of the Liberal Democrat ministers in the heart of government. Quietly, some might mention the spring Lib Dem conference that demanded change. Nobody wants to remind Clegg that he signed off on the original bill (apparently without reading it) and was joined in that support by Danny Alexander and the loyal Lib Dem MPs who voted for the unmodified bill thus far. From the Tories, Cameron has been equally firm in stressing that the changes are all his own work and nothing to do with the Lib Dems at all. Nobody wants to mention the fact that this has seen huge anger and remarkable unity of opposition from the NHS workforce, fed up with continuous reform and not wanting to waste any more money on a pointless and expensive restructuring rather than spending it on patient care.
Of course, what Clegg has done is put the Lib Dems squarely in the firing line over the NHS, so when a nurse drops a bedpan in Tredegar, it will not only echo around Whitehall and Andrew Lansley's office, but round every Liberal Democrat MP's constituency (Bevan's aphorism no longer applies, as the NHS in Wales is devolved). The NHS is a third rail in British politics - touch it and you risk political death. Thus far, the blame has rested squarely with the Tories - the Liberal minister being largely irrelevant in the public mind. But now, Clegg has again used his party as a sandbag to absorb some of the damage that will be thrown at the government and to protect the Tories. In that unfair way that the public have of apportioning blame, the truth of the matter will be irrelevant. Errors and problems will be as much Clegg's fault as Cameron's and with Clegg's popularity non-existent, he'll take the brunt of it for backing these reforms.
Perhaps the Lib Dems genuinely believe that the public will reward them for moderating the Tories wilder instincts. I think they're wrong. The public will continue to punish them until after the next general election. If the policies are perceived as good, then the Tories will take all the credit. If bad, then the Liberal Democrats will take the blame for not stopping them - moderation isn't enough.