The DUP is now publicly panicking over Brexit.

Last week, as the British government’s plan for a customs partnership with Europe following Brexit fell apart and both houses of parliament voted to stay in the European Union customs union, the DUP reportedly informed Downing Street it would also back customs union membership if that was the price of preventing a so-called sea border between Northern Ireland and the rest of the UK.

DUP leader Arlene Foster repeated this in a television interview at the weekend. Her deputy Nigel Dodds, the party’s leader in the Commons, said much the same in a magazine interview two weeks ago.

Both stated they would prefer the UK to leave the customs union, with Dodds saying failure to do so would be “the worst of all worlds”.

However, both added their only red line was keeping Northern Ireland in lockstep with Britain, whatever Brexit’s outcome.

If this achieves nothing else it should debunk claims the DUP is seeking a hard Brexit for hardline unionist reasons.

According to this hypothesis, which enjoys some credence in republican circles, the DUP or leading elements within it see Brexit as a last chance to drive an economic and physical wedge along the Border before the inexorable forces of demography, reason and love unite us all in a 32-county paradise.

Conspiracy theory

Theory has become conspiracy theory with the drip-drip of certain details, such as the DUP’s involvement with UK-wide Brexit campaigns, or the closeness of some of its members to Brexit activists in other parties.

The past two weeks have made it clear the DUP is not hoping to sabotage Irish unity through Brexit. However, this is not as accepted as it ought to be, even as the party runs scared of a sea border. Conspiracy theories attract diehard fans, this one flatters traditional suspicions about unionists and the British government, and investigations into Brexit campaign funding keep adding fuel to the paranoid fire.

DUP deputy leader Nigel Dodds. File photograph: Eric Luke/The Irish Times

The result could be the worst of all worlds for Northern Ireland politics, in which the DUP backs a soft Brexit and perhaps even plays a small part in delivering it, but where it never gets the credit because of its pride and nationalism’s mistrust. A chance for rapprochement will be squandered and Brexit will remain hugely divisive despite being technically resolved.

When Sinn Féin brought down Stormont the DUP accused it of using Brexit as an excuse, without accepting that if this conspiracy theory was true, the DUP had supplied the excuse

There are two keys to understanding the DUP’s true position on EU departure. The first is to realise that, like almost everyone else, it did not think Leave would win the 2016 referendum. This lured the party into believing it could indulge the pro-Brexit instincts of its members and supporters at no political cost.

Such instincts were not shared across the leadership. In an infamous interview just after the referendum, Stormont economy minister Simon Hamilton – Foster’s closest lieutenant – repeatedly refused to say how he had voted, leading to the universal assumption he had voted Remain.

The second key to the DUP’s position is that its Leavers were high-profile but low-powered, with no common philosophy.

There was a pro-Brexit caucus on Stormont’s backbenches, but its motivations ranged from free-trade fundamentalism through to various shades of British nationalism.

"Jeffrey Donaldson wanted a piece of the campaigning action and helped arrange the Metro newspaper ad that alerted journalists to its unusual funding."

The DUP’s centre of Brexit sympathy was at Westminster, among what were then its eight MPs. Dodds was a true believer in the free-trade vision and had been involved with its leading lights from the beginning. Jeffrey Donaldson wanted a piece of the campaigning action and helped arrange the Metro newspaper ad that alerted journalists to its unusual funding. Ian Paisley jnr appeared to enjoy the more purely flag-waving aspects of the issue, verging at times on simply winding opponents up.

Irrelevance

In 2016, it seemed safe to let all these people have their fun because the DUP’s MPs were an irrelevance – powerless in London and ignored at home, where all the focus was on Stormont.

For Foster, appointed leader just six months before the referendum, allowing her Brexiteers off the leash might have seemed like a harmless way to occupy the bored and potentially restless.

Everything that has happened since can be seen as the DUP having to take more and more responsibility for a position it never thought it would have to stand over.

After the referendum it tried avoiding ownership of Brexit within Northern Ireland, passing responsibility to the entire UK electorate.

When Sinn Féin brought down Stormont the DUP accused it of using Brexit as an excuse, without accepting that if this conspiracy theory was true, the DUP had supplied the excuse.

In the 2017 Westminster election, incredibly, it won 10 seats and found itself holding the balance of power, acquiring a national responsibility for Brexit. Now it is facing the fact that even this level of influence cannot offset the centrifugal forces unleashed against the union.

Did the DUP bring this on itself? Certainly. But that cannot have been its intention. Like the big beasts of Brexit it thought it could play with, the DUP has never had a plan.