So MPs have (narrowly) rejected the Lords' amendment to the EU Withdrawal Bill, which would (if passed) have given parliament the power to force the PM back into negotiations with Brussels if MPs and Lords reject whatever Brexit deal she ultimately negotiates. (Phew: that was a mouthful).
But the price Theresa May is paying for that victory - paying to Tory Remainer rebels led by Dominic Grieve - is that she has agreed to redraft the Bill when it returns to the Lords so as to account of Grieve's own amendment to the bill. After some fraught and dramatic negotiations, May is now conceding:-
1) That within seven days of her agreeing a Brexit deal, a motion to approve said deal must go to the Commons
2) That if there is no Brexit deal agreed by 30 November this year, the government must seek approval for its next course of action from MPs,
3) May will consider how to capture Grieve's other demand: that MPs and Lords must be able to instruct the government on how to proceed, should there be no Brexit deal agreed by 15 Feb 2019.
Arguably, this transfers considerable power to MPs over the shape of a future Brexit deal. And it probably means that a no-deal Brexit is no longer any kind of realistic prospect. So if May really believes she was able to put negotiating pressure on the rest of the EU by threatening a no-deal Brexit, she has now lost that leverage.
In other words, one of her favourite catchphrases - that no deal is better than a bad deal - is dead. And this will be made official in just a few days, when the bill returns to the Lords.
Robert Peston is ITV’s Political Editor. The is an edited version of a post on his his Facebook page