I am well aware that when it comes to the politics of EU leader summits predicting anything is hard. But today is a crunch day for David Cameron and a while ago he set a bad precedent by using his veto at such an event. Today there are four states who might feel like doing the same in return.
What if Cameron returns empty-handed? Does the referndum go ahead this year?
Does he then argue that what we have is the best deal and we should vote for it?
Or does he move to Brexit?
And what then? Jacob Rees-Mogg was gloating on the prospect of removing employee rights on Channel 4 News last night.
A move offered in haste to appease the UKIP wing of the Conservative Party is now looking very dangerous indeed. The EU may have awful flaws in it, but I believe they are better than being out. And out now looks to be increasingly likely.