Much hinges on how eager David Cameron is to confront this resistance, and hasten a policy that was more or less writ into his party's manifesto. In the weeks following the AV referendum, the Tory leader has been happy for Clegg to act alone as the scourge of an unelected Lords. But, without support, Clegg could just look like the fall guy, there to take the heat for yet another Lib Dem disappointment. And that, of course, has ramifications for the fragile balance of the coalition.
So will Cameron step in? There is much talk that he is planning to castrate the Tory right, and strengthen the ties that bind the yellow and blue components of his government. But I'd be surprised were he to be blatant about it in this case. Many Tories are already seething, on principle, about what is being done to the NHS reforms, as well as to the public service reform agenda in general. Stir in Lords reform, and the mixture could become combustive, with both Cameron and Clegg caught in the fires. The Prime Minister might prefer to let this one slip.