Brexiters should pay careful attention to the two messages they got from Europe today. One came from Michel Barnier and was encouraging. The other came from the European parliament and was not.

The parliamentary message came in the form of a draft resolution which will be voted on next week. It'll probably pass. It says that the second stage of Brexit negotiations covering future trade arrangements cannot begin, because not enough progress has been made on the Irish border, citizens' rights and the divorce payment. It also comments angrily on the repeated erroneous demands of the Home Office for EU citizens to leave.

Top line of draft resolution: "sufficient progress has not been made" in all three areas: 1/5 pic.twitter.com/9tletyV4gV — Faisal Islam (@faisalislam) September 28, 2017

Barnier's message came during a joint press conference with David Davis in which he said May's Florence speech had "created a new dynamic in our negotiations". We weren't there yet - there would still be "weeks or possibly even months" until the talks could move onto the second stage. But this was by some distance the most positive he has sounded. There was progress. Things no longer seemed to be stalled.

This is, in effect, the story of two Brexits. One is the crazed Brexit of a bunch of hysterics. The other is a rational Brexit which seeks a viable outcome via a realistic timetable.

The first means you tell the EU to "go whistle" over money and refuse to sign up to European law during transition. It deals in temper tantrums and ever-more desperate assertions of national superiority instead of careful preparation. It cares so little for immigrants that it starts sending out deportation letters to people who should never have received them. And it refuses to live up the promises it gave EU citizens to keep their rights exactly as they were at the point of the vote.

The other method recognises that we are in a highly technical and emotional negotiation with a far larger partner, where the consequences of failure weigh disproportionately on our side. It accepts that the process needs much longer than the current two-year timetable and that the mandate from Brussels demands the total adoption of EU rules during a transition. It is willing to offer money in order to grease the wheels of negotiation and to abide by the contractual obligations of the UK from when we were a member.

The first approach – throwing your toys out the pram – yields no results. That much has been clear over the last year. The second approach – being reasonable and realistic – means you can progress. The prime minister is a late convert to this, but better late than never.

That does not mean we are there yet. The transition is probably impossible unless the government makes up its mind about the final destination. Will it accept regulatory harmonisation and single market rules in return for trade or not? May doesn't seem to know. No-one around her seems to know. Without an answer on that there's nothing to transition to, as a point of basic logic.

There are many other obstacles. Whatever the final destination, a two year transition will not be enough. It'll be longer and the sooner Brexiters recognise that the better. Brussels also needs – and EU citizens deserve – a better offer on their rights.

This offer needs to be independently guaranteed. That could probably be the Efta court, rather than the European Court of Justice, but the Brits need to hurry up and accept the principle before quibbling over the mechanism.

May must also stop trying to get rid of family unification requirements. These take several forms, the most pernicious of which is the £18,600 income benchmark for those with non-EEA spouses. It is not tolerable for an EU citizen living in the UK and married to someone from outside the EEA to be faced with the prospect of being separated because they do not make enough money. No morally sane nation would demand this anyway, but it takes a really special form of ethical breakdown to allow it to be an obstacle in a broader political process of this magnitude.

The next six months are crucial. This is the period in which compromise arrangements can potentially be made. Some in Brussels and London think these sorts of compromises on transition are already impossible. After all, you need to somehow redefine the customs union, which is no small thing, and construct a legal category in which Britain takes all rules but does not have any MEPs. British domestic law has to find a mechanism to get rid of the European Communities Act 1972 while somehow still keeping it operating to all intents and purposes. Others think there is still just about enough time but that this really needs to be agreed by spring next year at the latest. Either way, clock is ticking.

Once it does pass, only the extreme options are left. On the Leave side, that means no-deal. On the Remain side, that means a change of heart or, more likely, a petition – which may or may not be accepted by the other EU member states - to extend Article 50.

If the Brexiters have any sense at all, they will see that the reasonable approach is far more likely to provide them with some form of eventual limited Brexit. The alternative will bring the country to the brink of the cliff edge, from which it will either change its mind or be flung off. Neither option would suit them. But to arrive at this realisation they need to accept that the UK is not in the omnipotent position they have fooled themselves into thinking it is. They need to sober up.

The question is this: After so long mainlining emotional nationalism, can they wean themselves off it in time to save what's left of their project? It's not at all clear they can. We'll find out in these next few months, one way or another.

Ian Dunt is the editor of Politics.co.uk. His book - Brexit: What The Hell Happens Now? - is available now.

The opinions in politics.co.uk's Comment and Analysis section are those of the author and are no reflection of the views of the website or its owners.