Ever since the government suffered a historic 230-vote parliamentary defeat on its draft Withdrawal Agreement (WA) in January, MPs, commentators and EU politicians have urged a cross-party consensus to solve the Brexit crisis.
Many observers believe that a parliamentary majority could exist for a soft Brexit by uniting moderate MPs in both major parties and leaving the backbench Conservative European Research Group in impotent opposition. Yet while this sounds appealing, it ignores fundamental attributes of Britain’s two-party system.
Two-party systems and multi-party systems
In two-party systems, policies that depend on temporary cross-party alliances may never emerge, even if they nominally command the support of a majority of MPs. That is because such alliances may cause deep-seated divisions in one or other existing party, weakening its internal cohesion.
The top panel of the diagram shows a two-party system in which the parliamentary strength of the two parties is indicated by the size of the boxes. Here, the centre-right party (B) enjoys a majority over the centre-left party (A) and forms the government.
Suppose a policy issue were introduced that internally divided each party’s ‘moderate’ MPs (those towards the centre of the diagram) from its respective ‘radical’ MPs.
Imagine further that a majority of MPs, drawn from each party’s ‘moderate’ wings, supported the policy and could pass a bill provided that they cooperated. This cross-party alliance is indicated by those MPs inside the dashed-line box.
Centrist cross-party policy proposals in two-party and multi-party systems
European multi-party systems, such as those in Germany or the Netherlands, would find it easier to forge cross-party alliances. One party rarely wins a majority in these countries, making inter-party cooperation essential.
In the lower panel of the diagram, the moderate parties of the centre-left (A) and centre-right (B) are joined by more radical parties of the left (C) and right (D). While a rightist alliance of B and D enjoys a majority, so does a more centrist alliance of A and B (parties inside the dashed line).
The policy arising from this deal would be centrist but also feasible, whereas in a two-party system it would destabilise both major parties.It would be risky for the government to rely on this temporary coalition of MPs to support its policy.
Once the measure had passed, there would no longer be any need for this coalition and so the government would have to maintain itself in office through its own MPs only.
But now, it would be riven with internal conflict between ‘radicals’ and ‘moderates’. If the division were very deep, the party might split in two. The temptation would be for the government to seek a compromise that drew a parliamentary majority from among its own MPs to preserve party unity.
Brexit and the UK party system
This contrast has clear relevance for the UK government’s attempts to navigate the WA through parliament. After the defeat of the WA, May sought to bring the ERG (and the DUP) on board rather than cutting them off and seeking a deal with Labour.
If the UK had a multi-party system, the ERG would likely constitute a separate party (like D above), and could be ignored by a more centrist government. However, in Britain’s two-party system, the ERG’s support is crucial if the Conservatives are to win parliamentary votes and avoid internal splits.
Consequently, the government, the ERG and the DUP joined forces in passing the ‘Brady amendment’ calling for the renegotiation of the backstop.
Critics of this approach have suggested several ways to break free of the constraints of the party system.
Each would involve cross-party alliances that side-lined the ERG. One option would be a formal cross-party deal between the government and Labour over a customs union.
A second would be an informal deal between the government and some centrist Labour MPs from Leave-voting constituencies who prefer May’s deal to no-deal chaos.
A third possibility is a free vote of MPs in both major parties, allowing parliament’s cross-party soft-Brexit majority to emerge.
That could also be enabled by a fourth option, being pursued by Nick Boles MP, of allowing parliament to usurp the executive and act as a ‘government’ itself over Brexit.
Each of these solutions would achieve a softer Brexit by ensuring that a cross-party majority could outvote the ERG. But they also share a fundamental problem. Each envisages a temporary cross-party coalition of MPs but none addresses what happens after its preferred Brexit deal is passed.
The country would still need a government, not least to pass legislation to implement the deal, but none of these transitory arrangements could provide it. There would be no Conservative-Labour grand coalition and no continuation of Boles’ executive-in-Parliament.
There would be a Conservative government reliant on its own 317 MPs with support from ten DUP MPs, as at present.
But in the aftermath of a cross-party alliance that cast aside hard-Brexiteers, the Conservative Party would be ablaze.
It would be beset by ministerial resignations, parliamentary discipline would break down, local parties would seek the deselection of pro-EU MPs, and eurosceptics would be demanding the prime minister’s resignation.
The governing party would be in a state of civil war and, in all likelihood, incapable of executing the functions of government. If the DUP withdrew its support – perhaps because the backstop had survived – the government could lose a confidence vote.
A minority Corbyn government would be a genuine possibility, an early election a strong probability.
The government’s preference is to pass any revised WA with Conservative votes. That might involve compromise with the ERG.
Or it might mean running down the clock and leaving Brexiteers with the choice of voting through the prime minister’s deal or seeing Brexit delayed, as Olly Robbins, Theresa May’s chief negotiator, was reportedly overheard saying.
But there are no guarantees that the ERG rebellion could be kept small.
May will face a huge dilemma if large numbers of Labour MPs, spooked by fears of a no-deal Brexit, move towards supporting her deal and guaranteeing her a parliamentary majority, while the ERG and DUP remained implacably opposed. If she pushed the deal through in these circumstances, the government could quickly fall.
The two-party system’s imperfect overlap with Brexit preferences constrains feasible Brexit outcomes. But that in turn causes intolerable strains within the main parties.
Speculation is rife of a new centrist party composed of Labour and Conservative moderates – particularly in the wake of the Gang of Seven’s split from Labour.
Yet such a venture would face an uphill task because of the electoral system and the in-built organisational advantages of the established parties.
Preserving the latter’s internal unity to ensure their survival for the post-Brexit era is therefore the Herculean but vital task facing Conservative and Labour party managers.
By Dr Tom Quinn, senior lecturer, University of Essex Department of Government.
The views expressed in this analysis post are those of the authors and not necessarily those of the UK in a Changing Europe initiative.