Yes, those really are vague pink glimmers in the early morning sky. Reality is dawning on the Brexiteers. Once, they were going to walk away from the European Union in March 2019, whistling Rule Britannia and greeting queues of foreign supplicants begging for trade deals. Now, they are hoping to cling on until June 2022. They know they are going over a cliff and realise that it is better to climb down slowly than to plunge off the top.

But this climbdown also creates a crucial weakness – one that explains why the Irish Government’s tone has changed so radically.

To understand this new weakness, we have to recall that there were two possible scenarios in which the Irish Government had very little power. One was that the UK would simply walk away from the EU without any deal, the car-crash Brexit for which British prime minister Theresa May’s old mantra, “No deal is better than a bad deal”, was meant to be the overture. If that happened, Ireland was completely impotent.

The other possible scenario was the straightforward one set out in article 50 of the Lisbon Treaty. The UK and the EU would negotiate a full exit deal by March 2019. In this case, Ireland would have very little power either. Even if the deal was a betrayal of our interests, we could not veto it.

The deal would have to be ratified by the European Parliament and then by the European Council. But, crucially, the council has to accept the deal only by a qualified majority. In both bodies, therefore, Ireland could easily be out-voted.

We could exert moral pressure but, as we’ve seen in our recent past, moral pressure from small member states can count for very little in European realpolitik. For all the fine words and assurances, Ireland would be relying on the kindness of strangers.

Balance of power

Not any more. If there is a new assertiveness in the pronouncements on Brexit of Taoiseach Leo Varadkar and Minister for Foreign Affairs Simon Coveney, it is because the balance of power has shifted in Ireland’s favour. The two scenarios in which Ireland has no real muscle are effectively off the table.

The dramatic shift in tone in the last two weeks is not accidental. It is the voice of the newly empowered

The “no deal” mantra has been exposed for the hollow nonsense it always was. But equally, because the British have wasted so much time and energy on ludicrous posturing and internal warfare, there is no chance of a clean, negotiated settlement coming into effect in March 2019.

Podcast: Dublin's tougher Brexit stance

Staggering as it seems, the British government is only now beginning to think about basic realities like the needs of its industries for immigration, how the planes will continue to fly, and the regulation of nuclear materials.

Hence its requirement for a long transitional period: even 2022, as mooted by UK chancellor Philip Hammond, may even be highly optimistic.

But – from an Irish perspective – this changes everything. Under article 50, it is indeed possible for the member state that is exiting to seek to extend the remit of the EU treaties beyond the stipulated two years.

This is what a transitional period would have to mean.

But – and here’s the rub – this can be done only with the unanimous consent of every other member state. In other words, Ireland has a veto.

We can now block the implementation of a transitional deal even if Germany and France and every other member state wants it to happen. The chaotic foolishness of the Brexiteers has, to coin a phrase, allowed us to take back control.

The Brexiteers don’t know this, of course – they haven’t given Ireland a moment’s thought.

More remarkably, the Democratic Unionist Party seems not to know it either, hence the idiotic twittering from Ian Paisley jnr about how Ireland will either have to accept a “very hard Border” or “wise up and leave the EU”. But the Irish Government knows it. The dramatic shift in tone in the last two weeks is not accidental. It is the voice of the newly empowered.

Let’s be frank: there is a conflict unfolding on this island and one side has just acquired a formidable weapon. The conflict is between two incompatible imperatives.

On one side is the DUP’s need to cover up its own foolishness by getting everybody to go along with the pretence that there is no real Border problem at all.

On the other is the Irish Government’s absolute need (and the need of the people of Northern Ireland) to avoid a hard Border on the island of Ireland. These desires are mutually exclusive.

The DUP’s new religious faith in the power of technological miracles to make the problems go away is touching, but the “frictionless” Border remains a fantasy.

So we now have two Irish vetoes. The DUP’s consists in having 10 Westminster votes to dangle in front of a weak, divided and unstable Tory government. The Irish Government’s consists in an absolute power under EU law to derail the whole Brexit process.

It reminds me of the scene in George Bernard Shaw’s Arms and the Man in which Bluntschli replies to Sergius’s challenge to a duel with sabres: “That’s a cavalry man’s proposal. I’m in the artillery; and I have the choice of weapons. If I go, I shall take a machine gun.”