The vote for Brexit plunged both the Conservative Party and the Labour Party into turmoil. It also provoked predictions of the further fracturing, and possible breakdown, of the party system.
In an article recently published in International Political Science Review, I assess the degree of party change Labour and the Conservatives have undergone in response to the external shock of the vote for Brexit, in terms of the leadership of each party and the factional conflicts both faced.
As the article explains, the Brexiteer faction of the Conservative Party was ultimately able to assert control of the party machine and effectively mobilise the Leave side of the Brexit cleavage, delivering electoral victory in December 2019 and the United Kingdom’s exit from the EU in January 2020.
This proved possible without causing an irrevocable split in the party as Brexit could be accommodated ideologically by most Conservatives, even those who had backed Remain in the referendum campaign.
In the case of the Conservatives, this process can be divided into two distinct phases – first a period of limited party change under Theresa May, followed by a radical transformation under Boris Johnson which saw the party effectively captured by its hard Brexit faction.
In the immediate aftermath of the referendum, David Cameron’s resignation prompted a change of leadership, but to the surprise of many observers the election was won not by a Brexiteer but by a Remainer, as the pro-Brexit faction of the Parliamentary Conservative Party failed to unite around a candidate and the strongly pro-Brexit party membership were denied a say in the outcome after Andrea Leadsom withdrew from the contest.
May nevertheless oversaw policy change as she defined the parameters of Brexit to include leaving the single market and customs union, tilting the party ideologically towards a hard Brexit.
Remainers continued to dominate the party leadership, however, and May was unable to negotiate a Withdrawal Agreement that satisfied the pro-Brexit faction in the Parliamentary Conservative Party .
May’s resignation provided the pro-Brexit faction with the opportunity to secure the party leadership. Johnson’s victory marked the factional takeover of the Conservative Party by its hard-Brexit wing.
In his seminal work on party change, Panebianco suggests that changes in the dominant coalition within a party can impact upon vertical power relations within the organisation.
This was witnessed in the Conservative case, as the leadership ultimately came to reflect the Euroscepticism of the wider party.
The prioritisation of Brexit above all else, the marginalisation and exclusion of dissenting voices, and the consolidation of power brought about by the 2019 general election victory, marked the completion of this process of profound party change.
The Conservatives had transformed themselves unambiguously into the party of Brexit. This enabled them to squeeze out pro-Brexit competitors (UKIP and latterly the Brexit Party) and effectively mobilise an electoral coalition based on the 2016 Leave vote which enabled them to move deep into Labour territory.
The rise of Eurosceptic sentiment in the Conservative Party over several decades meant that the vast bulk of the party membership and the Parliamentary Conservative Party had little ideological resistance to moving in this direction.
The main focus of concern for Conservative ‘Remainer’ rebels was the threat of a ‘no deal’ Brexit, which was averted by Johnson’s revival of a revised Withdrawal Agreement.
Johnson therefore provides a case study in how a change of leadership and dominant faction can drive seemingly dramatic party change over a relatively short period, but this needs to be understood within the broader context of deepening Conservative Euroscepticism since the late-1980s.
In short, the long-term ideological current of hardening Euroscepticism in the party eventually facilitated a process of rapid and far-reaching party change.
On the other side of the political divide, perhaps the most striking question is why did the Labour leadership not similarly come to reflect the overwhelmingly pro-Remain sentiment of the wider party?
This seems particularly curious given the nature of the Corbyn project, which was built on the support of the party membership and located its authority not in the Parliamentary Labour Party but the wider Labour movement.
The answer to that is twofold. First, Labour faced an intractable problem of electoral geography, with many Labour MPs acutely aware of the fact that they represented areas that had voted unequivocally in favour of leaving the EU.
Second, the Brexit referendum intersected with a wider process of party change which the Corbyn leadership represented and which was prioritised by the party membership, namely the reorientation of the party’s ideological and policy outlook in a much more radical left-wing direction.
Ultimately, Labour did reach a position of endorsing a second referendum at the 2019 general election, but only after a painful and halting process to which it was always clear the leader himself was very reluctant to fully commit.
Given Johnson’s capacity to unite the Leave vote Labour’s best hope at the 2019 general election was to do the same with Remain.
However competitor pro-Remain parties such as the Greens and the Liberal Democrats, and other issues such as the serious misgivings many voters had regarding Corbyn’s leadership meant that proved impossible.
The response of Labour and the Conservatives to the vote for Brexit consequently offers a fascinating case study of party change in response to external shocks, and of how substantial party change by the Conservatives effectively averted major party system change – for now at least.