Liz Truss's struggles as PM expose the flaws in party leadership selection rules

In debates over the future of Liz Truss’s premiership, it has been argued that it is illegitimate for her to depart from the agenda on which Boris Johnson was elected, and that she does not have a mandate for doing so. For example, Johnson supporter Nadine Dorries has claimed that Truss needs to call a general election to secure a renewed electoral mandate. The opposition has argued the same – unsurprisingly given their poll lead. 

From a constitutional point of view this is gibberish. The prime minister is the person most likely to command the confidence of the House of Commons. By winning the 2019 general election the Conservative Party secured a mandate from the electorate to run the country by winning a majority of seats in the Commons. In the modern era the person who is leader of that party can therefore assume control of that majority and the confidence of the Commons that it brings.

The mandate Truss secured from a majority of Conservative Party members was therefore all she needed to become the legitimate prime minister. Where the constitution comes into conflict with the leadership election is not in Truss being appointed prime minister, but whether it has contributed to a situation where she cannot maintain that confidence.  

Truss departed from the 2019 manifesto on spending not tax 

A separate question is what mandate Truss had to change policy direction. During the leadership campaign Truss was clear that she intended to govern as a small state, low tax conservative, but once she unveiled her radical agenda questions were soon asked, including by her own MPs, about whether she had a mandate to depart from Boris Johnson’s 2019 manifesto. 

In truth Truss’s plans on tax – now reversed – were closer than Johnson’s to the manifesto, which committed to no new income tax, National Insurance or VAT. It is Truss’s ambition to shrink the state that departs from ambitious 2019 commitments to address big issues like social care, digital and physical connectivity, and the delivery of "world-class public services".  

But in terms of Truss’s legitimacy – or that of any PM – it is misleading to focus too much on the manifesto. Voters may well judge politicians for delivering on their promises, but manifestos are not binding. As the pandemic and cost of living crisis have shown, external events can force prime ministers to depart from their election pledges.  

However, the 2019 manifesto's ambitious spending pledges were probably always incompatible with simultaneous promises to hold down taxes, reduce debt as a share of national income and not borrow to fund day-to-day spending. The extent of the incompatibility has now become painfully clear, first in Truss’s market-spooking inability to convincingly articulate how she would reduce the size of the state to compensate for lowering taxes, and now in Jeremy Hunt’s honesty about the difficulty of filling the black hole in government finances without tax rises and public spending cuts. So while voters may end up punishing the Conservatives for Truss's departure from manifesto spending pledges, departing from the manifesto does not make her premiership illegitimate. 

The measure on which it is appropriate to judge the legitimacy of Truss’s premiership is whether she is the figure most likely to command the confidence of the Commons. Given she has been in office for less than two months it is remarkable that this question has already arisen. She was not the first choice of Conservative MPs and now, following the dismantling of her radical economic agenda and the co-opting of Hunt as chancellor, there is real doubt about whether Truss truly commands the confidence of the Commons – with the frenzy of briefing suggesting any one of Penny Mordaunt, Rishi Sunak or Jeremy Hunt would be more likely to do so.

Party rules for selecting leaders are flawed 

Truss's struggles have exposed the flaws in how parties chose their leaders – less relevant when a party is out of office, but highly salient when in power and party members are selecting the prime minister.  

It has been widely argued that the Conservative Party leadership process was anti-democratic because the preference of a majority of MPs, who had close knowledge of the candidates and represent millions of voters, was overridden by the votes of a few tens of thousands of party members – who tend to be more right wing than their MPs. In Labour's case, the party’s membership may be larger than the Conservatives, but the same tension between the will of MPs and that of Labour members – who tend to be more left wing – was evident when Jeremy Corbyn was elected. 

And on recent evidence it seems that party processes have picked leaders who have neither the support of a majority of their MPs or the capability to govern as well as they campaigned. This undermines their ability to get things done in parliament, so on the basis of good government there is a strong case for changing the process by which parties choose their leaders. Truss’s ability to fulfil the party leader’s role of providing cohesion and direction to MPs, and hence to command the confidence of the Commons, is made even harder as parliamentary parties are more fractured and less obedient than ever before following the rebellious Brexit period and Covid restrictions, which reduced network and loyalty building among new MPs.

Parties should revisit their rules on choosing leaders 

This is bad for government because it means ministers will struggle to deliver on their plans. It may also damage trust in government if politicians repeatedly promise to deliver policies they then prove unable to get through parliament. And the Conservatives' leadership election rules may also be bad for the party’s electoral prospects. Truss has demonstrated how it is possible for a leader elected mid-term to move dramatically away from a party’s manifesto in a way which appeals to her party base but – based on polls of voting intention – has not attracted the broader electorate.  

Both the Labour and the Conservative parties should reflect on the processes they have in place for selecting leaders. Existing processes may generate constitutional legitimacy and a mandate from party members, but are highly problematic if they lead to a government that is unable to command the confidence of its own MPs, particularly in times of crisis. Reducing the influence of party members may prove unpopular with the base but may nonetheless be essential if parties are to secure effective leaders that can command confidence and run an effective government – delivering a policy programme through parliament and winning the trust of the markets and of voters.