In his ConHome diary last week, Iain Dale asked one of the key questions of this general election campaign: how vulnerable is the Conservative Party to the Liberal Democrats?
To put it another way: in the country-at-large, how many voters are there like David Gauke? That is, pro-Remain former Conservatives for whom Brexit is the central issue.
At present, it looks like the Liberal Democrats have a good run at just over a dozen Conservative seats, stretched a little further if the ‘Remain Alliance’ really works.
The party’s strategy hinges on reaching into this part of the Conservative Party’s electoral coalition, while also not alienating potential Labour switchers. It is a tough balancing act, but it makes political sense.
After all, in terms of electoral geography, Conservative seats are where many of the plausible gains for the Liberal Democrats lie.
On a uniform swing, 20 of their 25 most gainable seats are Conservative held.
They should be helped by the Conservatives’ positioning under Boris Johnson as the party of Leave, having eclipsed the Brexit Party. This may alienate pro-Remain Conservatives, who represent a sizeable chunk of the electorate.
According to British Election Study (BES) data, since December 2016 pro-Remain Conservatives have made up around 26% of the party’s voters.
If we apply that percentage to the Conservatives’ vote at the 2017 election, that’s some 3.5 million voters.
Even UKIP, who perhaps have had a larger impact on the Conservative Party in recent years than anyone else, only reached 3.9 million votes at their zenith in 2015.
By any definition, pro-Remain Conservatives could be decisive in this election. So how might they vote?
There are some grounds for optimism for the Liberal Democrats.
As the chart below shows (using data from the latest BES wave in June), Conservative Remainers are much less likely to identify with the party than Conservative Leavers.
Almost 40% of these voters don’t feel that they are big-C Conservatives by identity. This suggests a substantial share of them are up for grabs for other parties.
Whether they would lend their votes to other parties depends on their view of them.
It might seem obvious that these voters would dislike Nigel Farage, given that they support Remain, and they do. But they actually dislike Jeremy Corbyn, who by any account is closer to their view on Brexit, even more.
This clearly explains the Liberal Democrats’ openly hostile posture towards the prospect of Jeremy Corbyn as prime minister. Anything that smells of Lib-Lab co-operation is likely to put off this group.
It is the Lib Dems’ inoffensiveness, in stark contrast to Boris Johnson and Jeremy Corbyn, that makes them an electoral option.
That makes their aggressive positioning on revoke high risk because on Brexit, as opposed to economic questions, they cannot present themselves as the moderate, middle ground option.
Conservative Remainers are caught in a bind: against Brexit but also against Corbyn. Their votes will depend on whether they can be persuaded that not voting Tory means avoiding both.
If not, it may come down to which is the bigger threat for these voters.
By Matt Bevington and Dr Alan Wager, researchers at the UK in a Changing Europe.