Jon Tonge: Big risks if DUP removes influence at Westminster over Brexit border backstop
The pledge by the DUP's Westminster leader Nigel Dodds to paralyse the Conservative Government's legislative agenda if a border in the Irish Sea emerges seems bold.
It begs the question though: what legislative agenda?
Consumed by Brexit legislation, Theresa May's government produced the thinnest Queen's Speech ever in terms of normal politics.
Quite what would be achieved for Northern Ireland by the DUP's Westminster Ten (currently nine) downing the remaining legislative items is unclear.
Stopping the extension of compulsory insurance to automated vehicles, preventing the licensing of vertically launched space rockets and resisting the spread of smart meters into homes might give visceral pleasure.
It's hardly 1974 Ulster Workers' Council constitutional stoppage territory though.
Having already banked more than £400m for Northern Ireland, the DUP risks losing the other £600m promised.
Budget-breaking is the DUP's big Westminster card.
The numbers simply do not stack up if the DUP swaps sides and votes against the Chancellor.
Opposition forces reach 326; government 315. Game and set to the DUP, if not the match.
What would follow would be zombie government, unable to operate.
A defeated budget would create a crisis almost certainly triggering a vote of confidence in Theresa May's hapless administration.
But the DUP has already indicated it would support the government in such a vote - which rather blunts their swords.
And, in any case, there is now precious little prospect of there being an unsatisfactory deal presented to the DUP this side of Budget Day, October 29. October 30 might be another matter.
Only a year ago, at the DUP reception at the Conservative Party conference in Manchester, Nigel Dodds happily lauded a "five-year deal".
Two months later, the souring began, the DUP refusing to accept a Brussels-shaped agreement unless full GB-Northern Ireland regulatory alignment, with no new regulatory checks, was maintained.
Everyone knew that this would be difficult to square with what remained in the December text regarding Northern Ireland's continuing trade alignment with the EU.
And, unless there is now some dancing on the head of a pin over what constitutes new or merely extended regulatory checks, the text remains impossible to truly reconcile. The DUP say they don't fear another election - and why should they?
Notwithstanding all the controversies surrounding the party, in the hermetically sealed ethnic blocs that constitute much of the Northern Ireland electorate - or its voting part at least - the question is potentially not so much whether the DUP can hold on to their 10 seats, but whether they can take Lady Sylvia Hermon's.
And another hung parliament might yet leave a DUP 11 with influence.
More immediately, however, the DUP may be about to forsake their influence in this Parliament.
Some 76% of DUP voters - and 75% of unionist voters more broadly - said after the 2017 election that they supported the DUP-Conservative link and only 2% of DUP voters declared themselves opposed.
But the essential problem for the DUP is that the more the Conservative government softens Northern Ireland's Brexit, the greater the chance of cross-party acceptance of the deal.
If the Prime Minister can attract sizeable support from Labour - still a mighty task it must be said - the DUP 10 matter much less.
The powerless vista is bleak. Removed from power in Belfast and self-removing from power at Westminster isn't a great sell for Arlene Foster to take to her party conference next month.
But, as ever, the DUP are not bluffing in their current demands.
- Jon Tonge is professor of politics at the University of Liverpool