By Darren Hughes

In these turbulent times, a leadership election feels almost a return to relative political normality - a process we've seen before, candidates setting out their stalls, vying for support from their colleagues. It's almost reassuring. But in truth, the race raises serious questions about Britain's constitution.

These issues are likely to get overlooked as the leadership show rolls on. But we need to address them now.

Who exactly is the prime minister accountable to?

If the current Conservative leadership race goes through to a ballot, this will be the first time party members have directly elected a prime minister. Recent changes of leadership out of election time have either happened without a full contest (as in the case of Theresa May or Gordon Brown) or been left directly in the hands of MPs (as under the previous Conservative election rules).

Prime ministers are chosen on the basis of who can command the confidence of their parliamentary party and the House of Commons as a whole. Yet this decision being in the hands of 160,000 unknown and unaccountable party members is quite a departure from our elected representatives wielding the power (and being nominally accountable for their decision).

After all, what happens if the person the party members select can't command the confidence of their own divided party, let alone the whole house? Boris Johnson topped the first round with 114 votes, enough to get him through to the members ballot. But at just 36% of Conservative MPs, it falls short of confirming majority support within his parliamentary party, let alone the Chamber as a whole.

What are the consequences if the new prime minister is seen as a direct delegate of the party's members, rather than the 'first among equals' of the Cabinet? This could also be seen as a step towards a more presidential, primary-based style of politics in the UK but without any of the checks and balances found with this model.

Do they have a mandate to govern?

The election also raises the issue of what kind of a mandate any new prime minister holds. Several of the candidates have claimed that they would have a fresh mandate to renegotiate Brexit, or to deliver it on new terms, but it's unclear why that would be the case.

The 2017 Conservative manifesto committed the party leaving the EU with a deal – but with many of the leading contenders committing to leaving on October 31st deal or no-deal, they are instead seemingly basing their legitimacy on the mandate from the 2016 referendum. They are pledging allegiance to a more direct model of democracy than our traditional Burkean representative approach.

There's another difficulty: the 2017 Conservative manifesto did not win a parliamentary majority, let alone a majority of the popular vote.

With an unclear mandate, the Lords could rear their heads. Could they try and block any of the new leader's policies that were not in the 2017 manifesto? The longstanding Salisbury Convention allows the Lords to delay policies that were not in the governing party's election manifesto – but with a new leader and a new agenda how will this convention hold up?

Do we need a fresh general election?

These tricky debates all lead to the same question: should the new prime minister be made to call a general election? All the candidates have ruled this out, with many warning that it would be a disastrous outcome for their party and the country.

When Brown took over from Tony Blair in 2007 there were vociferous calls for a fresh election – including from Boris Johnson – that ultimately fell on deaf ears. Only Anthony Eden, upon taking over from Churchill in 1955, has called an election within weeks of becoming prime minister. Others have continued to serve on their party's existing mandate.

But there's a difference this time round. Previous PMs installed by their parties had the safety of a parliamentary majority to allow them to continue to govern. May's successor does not. The new prime minister faces minority status, a requirement to renegotiate a confidence-and-supply deal with the DUP, a sizeable number of backbenchers prepared to bring the government down in the event of No Deal, and an Opposition which is relentless in its call for a general election.

Whether the candidates are right or wrong to rule out an election depends on your perspective on the role, mandate and flow of accountability of a prime minister in 21st Century Britain. The answers to these questions aren’t obvious. But what is clear is that we are striding blindfolded into some very strange constitutional waters.

The next prime minister will likely be the one to deliver Brexit – the biggest constitutional change our country has seen in generations. That means these constitutional questions aren't technical – they have major real-world impacts. And in turn, that means finding the answers is vital.

Darren Hughes is chief executive of the Electoral Reform Society.

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