Brexit is reaching its grim moment of truth - and the Brexiteers know it

In the United States, a country where Cabinet members now resign with great regularity, the departures of David Davis, the British cabinet minister responsible for Britain leaving the European Union, and Boris Johnson, the shaggy-haired Foreign Secretary, may not seem like much of a story.

Theresa May, the Prime Minister, for the first time in two years set out some concrete proposals for Britain's future relationship with its most important trading partners.

Davis and Johnson didn't like them. One quit yesterday; the other quit today. So what?

Although there will doubtless be some amusing anecdotes to be told about Johnson, who has stayed on at the Foreign Office despite gaffes that would have sunk anyone else, their departure isn't the interesting piece of the story.

Far more gripping is the fact that at no point - not in their resignation letters and statements, and not in the interviews they've given to date - have they or any of their Brexiteer colleagues offered what might be described as a viable alternative plan.

That is because there isn't one.

Or, to be more precise, there isn't one that satisfies them, the Europeans, British business and British workers.

There isn't one that corresponds to the ludicrous promises they made.

They cannot come up with something that, on the one hand:
- avoids any jurisdiction of European courts of any kind;
- avoids any payments into a European budget;
- avoids all membership in a European customs union and allows Britain to do trade deals with other countries;
- while, at the same time, keeps supply chains running smoothly;
- keeps the Irish border open;
- preserves tariff-free trade with Europe;
- and imposes no costs on anybody.

And all of this by next October in order to leave the following March. It just cannot be done.

The only deal they can genuinely offer - the only one that fits their definition of what Brexit means - is the no-deal deal.

That means Britain crashes out of all of its trading and customs arrangements with Europe and, without the bureaucracy to cope, has, for some period of time, a great deal of trouble importing and exporting anything to Europe at all.

Britain's Prime Minister Theresa May gives a statement to Parliament today. Photo / AP

Because this would cause major economic disruption, none of the Brexiteers wants to put his or her name on it. And so they leak to the newspapers, complain about the Prime Minister - and, now, resign.

There is a separate set of questions to ask about the Prime Minister's current plan, an arrangement that would theoretically keep Britain inside some of the EU trade agreements (at least those for goods that have to cross borders) and outside them for others.

This is precisely the kind of thing Britain should have come up with 18 months ago: it's the beginning of a negotiation.

Some of it will work, and some of it won't fly. Alas, there is very little time between now and the time Britain is due to leave for European institutions to work out the details.

But what May actually proposed matters less than the fact that we may finally have reached the moment of truth: The Brexiteers don't have an alternative plan, or at least not one that they want to talk about in public.

Nearly a year ago, I wrote that the Brexiteers' referendum lies were slowly being revealed.

Their cowardice is being revealed as well.

It will be interesting to see whether they pay a political price.