The snap general election has frozen Labour’s internal struggle for power.

Thanks to powers that the party’s National Executive Committee voted itself during Jeremy Corbyn’s first year as Labour leader, when there was a narrow Corbynite majority – now hung after the appointments of the Scottish and Welsh leaders are taken into account – anyone who stood for Labour in 2015, whether they were successful or unsuccessful, will be able to re-stand without going through a full selection.

In marginal seats, Labour’s candidate pool will look very different. Many Corbynsceptic candidates have no appetite to take 50 days of unpaid leave to lose an election. So if Corbyn can turn around the polls and win the election, the resulting parliamentary Labour party will be a Corbynite one, particularly as the PLP’s centre will fall behind the leader.

If the polls and the pundits are proved correct, however, then what matters most are what goes on in the party’s safest seats. For the most part, many of the party’s old warriors, who planned to stand down in 2020, are extending their parliamentary careers to avoid allowing their seat to fall to the other side.

Of the 12 Labour MPs who have stood down at time of writing, four are in seats that are widely expected to fall to the Tories.

Any vacant seats, whether held by Labour or the Conservatives, will be decided by the nine officers of the NEC; that is Jeremy Corbyn, his deputy Tom Watson, plus Jim Kennedy of Unite, Andy Kerr of the Communication Workers’ Union, Keith Birch of Unison, and Cath Speight of the GMB, with Ann Black, an ever-present on the party’s NEC since 1998, representing the membership. Rounding off the set are Diana Holland, the party’s treasurer, and Glenis Willmott, the leader of the party in Europe. Holland assistant general secretary of Unite, effectively giving that union two representatives, while Wilmott does the same for the GMB.

That means that as far as Corbynites and Corbynsceptics are concerned, the officers, like the NEC as a whole, is hung between Corbynites and Corbynsceptics.

In practice what will happen is that the three big unions will divvy up the seats, with the leader’s office making entreaties on behalf of their favoured candidates. The relationship between Lisa Johnson, political director at the GMB, and Anneliese Midgley, her opposite number at Unite, will be a critical one in deciding who makes the cut.

Although meetings of the NEC officers will likely be “fractious” as one insider puts it, ultimately the end result will be a deal that leaves the big unions happy. So while the leader’s office has a good chance of getting its people in when they have strong union links – Karie Murphy, Corbyn’s chief of staff and a close ally of Len McCluskey has been described as the “number one priority” as far as seat selections are concerned – for the most part, the big winners of these selections will be not diehard Corbynites, not bitter-end Corbynsceptics, but longtime union officials.