There was a great deal of speculation back in June about whether the election resulting in a hung parliament - albeit, crucially, one in which the Conservatives and DUP held a majority between them - made a hard Brexit significantly less likely. The theory was that Labour would wield much more influence, and that even the DUP would help steer the government towards a softer Brexit because of their pragmatic desire for a 'frictionless frontier' with the Republic. Well, the latter point is now looking distinctly ropey, because the one and only reason a hard Irish border even remains a possibility today is because the DUP vetoed the deal yesterday. It's still the case that the DUP would probably sign up quite happily to a soft Brexit as long as there were explicit guarantees that the degree of 'softness' would be uniform throughout the UK, and that Northern Ireland wouldn't end up in a 'one country, two systems' scenario. But any such guarantees would trigger a mass Tory rebellion and quite possibly bring the government down.
The trouble with trying to bounce people into an agreement they wouldn't ordinarily sign up to is that you have to move so fast that they don't know what's hit them until it's too late. The gambit almost worked yesterday, but a miss is as good as a mile, and Theresa May's game has now been well and truly rumbled. Having taken such open satisfaction in foiling Dublin's plans, the DUP will presumably only be able to get back on board if the Irish government are seen to publicly back down on points of substance, and that's surely very unlikely. Meanwhile, Tory Eurosceptics are now wise to May's willingness to concede a soft Brexit if that's the only way of squaring the Northern Ireland circle, and they'll move over the coming days to close that option off. Where else is there to go?
Right at this moment, it does appear that the loss of the Tory majority has - against all expectations - created a dynamic that makes a hard Brexit more likely, not less so.