Tonight the Lib Dems are refusing to accept defeat and insisting that Lords reform is not dead.
In an interview with me, Lib Dem MP David Laws made clear that the Tories would pay a heavy price for a failure to deliver. He told me that the failure of one party to honour the coalition agreement could result in a "chain reaction" and could jeopardise agreement on other areas of policy.
He said: "My colleagues in the Lib Dem party will say, 'Look if the Conservatives are not keeping their promises to us why should we keep our promises to them.' So that's very dangerous."
And he added: "If you start having parties pick and choosing what they're going to support and what they're not going to support from the coalition agreement, very rapidly you could run the risk of finding it difficult to agree and take forward policies in all of the other areas.
"So it's in the interests not just for the coalition but the whole country that both coalition partners honour the pledges that they made in all sincerity to each other two years ago."
"I can't speculate on the consequences of the Conservatives or the Lib Dems voting down a particular part of the coalition agreement but what I can say is it doesn't require much imagination to realise that you can set off a chain reaction... and that's why Nick Clegg and David Cameron are absolutely passionate about honouring the pledges they made to each other."