Doing the sums
When the margin of victory or defeat is so small, there are always plenty of factors that can claim credit or blame.
But in the House of Lords, the arithmetic of recent government defeats is becoming pretty clear: it's the crossbenchers who are hurting ministers.
In the St Valentines Day defeat over the under-occupancy penalty the government wants to add to the regulations in the Welfare Reform Bill (the so-called bedroom tax), 11 crossbenchers voted for the government and 58 against. In last week's Health and Social Care Bill report stage vote on the duties of the secretary of state to promote improvement in the treatment and diagnosis of mental health problems, they broke against the government again. This time it was 18 crossbenchers voting with ministers and 65 against.
And on the 31 January vote on the rate of Universal Credit for disabled children, 16 crossbenchers supported the government and 60 voted against.
To be sure, the pattern is not unvarying. The crossbench vote was much more evenly divided when the government was defeated on the powers of entry of officials to people's homes, on 6 February. Then, the split was 24 crossbenchers voting with the government, and 39 against. But in all of these four recent defeats, the overall majority against the government was quite tight - ministers lost by 10 votes on Tuesday, by four last week on the Health and Social Care Bill, by 12 votes on that Protection of Freedoms Bill amendment and by 16 on the disabled children amendment.
In all of those cases, they would have won comfortably, if the crossbenchers had split evenly. The votes of the bishops, of Lib Dem rebels and "others" would not have been enough. So while, on some of the tightest recent votes, it is possible for the government whips to point a finger at the small band of recent Lib Dem rebels - (it's getting to the point where the sight on one particular Lib Dem baroness voting with the government would constitute a decent story) - their real problem is the recurring opposition of the non-party peers.
You have to go back to the mega-defeat on the Welfare Bill over child maintenance to find an issue where the government would still have lost had the crossbenchers split 50-50 - and that owed a great deal to the substantial rebellion of Conservative veterans who joined Labour (and most crossbenchers) in the "content" Lobby.
Once, Labour peers tended to dismiss the crossbenchers as crypto-Tories. Now they find them a reliable ally in their gutting of a series of big government bills. The many senior lawyers and judges on the crossbenches have taken against many of the government's policies on "process" grounds - they think they're simply unfair.
There's an increasing contingent of crossbenchers with a background in voluntary work, social care and social campaigning and they have proved effective opponents for ministers - Lord Best and Lady Grey-Thompson spring to mind.
And there is a large contingent of very senior ex-civil servants who have weighed in against the government as well - and that's before we get to the retired generals and admirals, who have never hesitated to turn their fire on any government.
The crossbenchers have realised they have power and have begun to use it. Perhaps they're mindful that Lords reform could remove them from Parliament - but at the moment they have become a formidable barrier to government legislation… and they've hardly started on the Health Bill.