The Labour party is due to debate changes to leadership rules that would make it easier for left-wingers to stand.

Party moderates are plotting to block the changes.

Plans to permanently block another left-wing candidate also under consideration by moderates.

Party conference is "on a knife edge" over changes.

LONDON — Last year's leadership contest seemed to settle the question of who leads the Labour party for good. Jeremy Corbyn's landslide victory with 62% of the vote seemed to put to bed any hope among so-called party "moderates" that his leadership could be overturned.

But while the question of who leads Labour may be settled for now, the question of who succeeds Corbyn is not.

And while most of the attention has so far focused on possible left-wing successors such as Clive Lewis, Rebecca Long-Bailey and Angela Rayner, the reality is that it will be incredibly difficult for anyone from Corbyn's wing of the party to replace him. Here's why.

The leadership rules are stacked against them

Under Labour rules, anyone wishing to stand for the leadership must gain the support of at least 15% of the party's MPs and MEPs. The only reason Corbyn was able to overcome this hurdle in 2015 was thanks to Labour MPs such as David Lammy and Sadiq Khan who lent their support to him in order to ensure the "widest possible debate."

While they certainly got that wide debate, they also got a surprise takeover of the party by the left. Labour MPs are not likely to make that same mistake again.

The left of the party realise this, which is why they are so reluctant to let Corbyn stand down now, despite his terrible poll ratings and the looming electoral catastrophe facing the party. As things stand, when Corbyn goes, so too does the left of the party. However, they have a possible solution.

The McDonnell amendment

When Labour meets for its party conference in the autumn, they will face a battle for the very future of the party. On the agenda will be the question of whether party rules should be changed in order to lower the threshold for nominations for the leadership from 15% to just 5%. Those on the centre and right of the party have dubbed this the "McDonnell amendment" because of their belief that it is designed to ensure shadow chancellor John McDonnell succeeds Corbyn.

Those on the left of the party dispute this, saying that McDonnell does not even want to be leader. McDonnell himself has repeatedly denied any intention to run for the leadership and instead seems intent on promoting the future of the shadow business secretary Long-Bailey. Supporters of Clive Lewis also believe that he would be most likely to benefit from the change. But whoever the amendment is designed to benefit, the centre and the right of the party are determined to block it.

Can the amendment be blocked?

Yes it can. While there has been a surge of new members to the party since Corbyn first stood, the constitutional arrangements within the party are decided by the party's ruling executive and party conference, rather than exclusively by members.

The conference is split 50/50 between unions and members with delegates believed to be skewing slightly to the centre left and the unions split. As things stand this means that the so-called McDonnell amendment could fail.

"It's on a knife edge" one of those leading the charge to block the amendment told Business Insider. "It could go either way."

The fact that the decision is even in doubt shows the changes that are going on behind the scenes in Labour. While most of the coverage of the Labour party has focused on the lurch to the left among members, the centre and right of the party are increasingly winning selection battles in local CLPs and regional board elections.

Talk last summer of left-wingers triggering the deselection of sitting Labour MPs have so far failed to materialise. Meanwhile the Corbyn-supporting group Momentum remains engaged in an apparently endless bout of infighting. As things stand the "moderate" wing of the party seems better organised and on the ascendant. Indeed some on that wing of the party believe they could go even further and permanently exclude left-wingers from the leadership.

A return to an electoral college

One plan under discussion is to engineer a return to the electoral college system that elected every leader until Jeremy Corbyn.

Under this system party members, affiliates and parliamentarians make up three thirds of the electoral college, giving disproportionate voting power to MPs. Returning to such a system would make it virtually impossible for somebody like Corbyn to win again.



We're not counting our chickens but the numbers are better than last year

One figure pursuing the change told Business Insider that they were "increasingly confident" that such a change to the constitution was now possible. "We're not counting our chickens but the numbers are better than last year," they said. However others on the moderate wing were more sceptical.

"This is just wishful thinking" one said. "The only way such a motion could get into conference would be through the NEC [National Executive Committee] which is too finely split to pass something like this".

A similar change was proposed last year by Deputy Labour leader Tom Watson as part of a wider package of reforms, some of which would have been acceptable to the left. "There's no carrot this time, just stick," one leading moderate told me of the new proposals. "This couldn't pass. We need to just concentrate on blocking the McDonnell amendment."

However, the fact that such a change is even being considered by moderates reveals the shifts that are happening behind the scenes in the Labour party. While Corbyn's future as leader looks settled for now, the future of who rules the party he represents is still very much up for grabs.