Swinson's Article 50 pledge flirts with disaster – but it could end up grabbing ‘revenge votes’ for the Lib Dems

There’s a lot to be said for clarity. You’ll know this if you saw the clip of Labour’s Emily Thornberry on Question Time a week or so back tortuously trying, and failing, to explain her party’s Brexit policy. So the Lib Dems’ decision to declare that they will be revoking Article 50 if they win a majority at the next general election clearly has a lot going for it. But it also comes with dangerous downsides.

One thing it certainly does is distinguish the Lib Dems from Labour. There’s no way that Corbyn can match that offer. So for those who think “bollocks to Brexit” (which Lib Dem activists, I learned down in Bournemouth, like to sing to the tune of Waltzing Matilda), Jo Swinson really is the only game in town.

As such, Revoke is essentially a heat-seeking missile aimed at die-hard Remain voters in the constituencies, most of them Tory, that the Lib Dems have a pretty good chance of winning as long as, that is, the anti-Brexit vote isn’t split.

True, even precision-guided weapons tend to result in some collateral damage. There will undoubtedly be some less-convinced Remain voters who will be put off by a policy that Labour and the Tories, having promised to implement the result of the 2016 referendum, are already labelling (without a great deal of justification some would say) as “undemocratic”.

But if we’ve learned anything from the last three years, it’s that you really can’t have your cake and eat it. In politics, trade-offs come with the territory. And under first-past-the-post in particular, as the Lib Dems know better than anybody, it’s not simply about how many votes you get, it’s about where you get them.

Doubters, some of them brave enough to voice their concerns about the policy down among the faithful in Bournemouth, worry that it will remove any chance they have of winning back some of the Eurosceptic south-west seats that, until they lost them in the post-coalition catastrophe of 2015, they’d held through a combination of atavistic partisan loyalty and bloody hard work.

Well, they may be right. But, although candidates fighting those former bastions of liberalism won’t like to hear it (and may of course prove everyone wrong) those seats are very probably lost to them anyway. So if Revoke opens up possibilities in, say, London, where seats are genuinely in play, then that may well be a price worth paying.

A bigger problem, perhaps, is that the policy is based on a transparent falsehood, fallacy and fantasy – namely that the Lib Dems are going to win the overall majority that will allow them to implement it.

Sure, stranger things have happened. But right now, it’s painfully obvious that far fewer voters than ex-Labour and ex-Tory MPs are coming over to the Lib Dems. Current polling puts them at around 20 per cent, if that. True, political geography, as we’ve already pointed out, matters. But, unless the numbers change significantly, it’s going to have to weave some pretty dark magic to get them nearer to 330 than 30 seats in the Commons.

During any election, then, Lib Dem spokespeople are almost certainly bound to find themselves forced by the media to admit that their central policy is undeliverable. They will be accused of making a promise they can’t possibly keep, and asked if they risk letting down their supporters like they did over, oh, I don’t know, the abolition of university tuition fees.

They may be able to handle that (they could argue that if they can’t get what they want, then they will resume their call for a second referendum at which they will campaign for Remain). However, a trickier question would follow – namely, are they really saying, as Jo Swinson appears to be, that she won’t under any circumstances help put Jeremy Corbyn into Downing Street, even if that ensures a second referendum will take place?

Would doing that really be worse than happily entering into a coalition with David Cameron which, they’ll be reminded by Labour, unleashed five years and more of austerity on some of the country’s most vulnerable people?

And all that ignores what some see as Revoke’s biggest risk of all. It relies on Brexit not happening before the next election.

If Boris Johnson pulls off a miracle and takes the UK out of the EU by the time we troop back to the polls again, then the Lib Dems are going to look not so much like one-trick pony as a no-trick pony.

But hold your horses. That supposedly doomsday scenario might not be such a disaster, after all – at least for the Lib Dems if not for the country as a whole.

If we do leave, not everyone will be chuffed to bits or simply heaving a sigh of relief. And even those who are will soon find Brexit ain’t really over. As for those who aren’t, they will be angry – really angry – and they won’t be much less angry with Jeremy Corbyn and the Labour Party than with Boris Johnson and the Tories.

At that point, “revenge voting” could become a thing – and perhaps a very big thing for Jo Swinson and the Liberal Democrats.