Ed Miliband’s premature resignation was bad enough. It plunged the shellshocked Labour party into a leadership contest before it had time to absorb its general election defeat or to draw wise conclusions. Everything that has happened since has only made that initial decision seem more irresponsible. Labour MPs are now consumed by an inward-looking leadership contest. This brings out the worst in the Labour party. It also offers no guarantee at all that it will help answer the big questions that loom over its future.

Tristram Hunt’s announcement today that he is not entering the contest ought to set the alarms ringing again. That’s not because Mr Hunt is necessarily the ideal person to lead Labour. No one can say whether he is or not. But his is a voice worth hearing and now it will not be. Neither he nor any of the other possible candidates has yet had a proper chance to develop their ideas or their 2020 visions. Like Chuka Umunna before him, Mr Hunt has now withdrawn precipitately from a debate in which his ideas could and should have been properly heard and his candidacy thoughtfully assessed on the evidence.

Much of this is the fault of Labour’s leadership election system. At its malign heart is the process of nomination. To stand, a candidate needs the support of 15% of the party’s MPs. This bar – currently 35 MPs – is ridiculously high. In the Tory party, a candidate requires just a proposer and a seconder, which is a better and more open system. The problem is compounded by the candidates’ interest in amassing as many nominations as possible, which drains the pool still further. This happened in 2007 and 2010; now it is happening in 2015 too. Labour’s way squeezes out candidates and visions before things have even started. It lacks transparency. It takes power away from the voters. It is old-fashioned and absurd.

It also hands too much power to the power brokers – up to 130 of Labour’s MPs have backing from the Unite union, which has warned Labour to choose the “correct leader”. The nominations obsession encourages the sticks and carrots beloved of machine politicians – “nominate her and you’ll never get a shadow job” – while squeezing daylight and air out of the process ever further. Some 53 Labour MPs are new to Westminster. They haven’t even heard a single speech by any of the candidates. But a lot of them have decided who they are nominating. This is more than absurd.

In the Guardian’s view it is an outrage that Labour MPs are deciding the shape of this important contest so prematurely. No candidate has published a detailed argument about why Labour lost and how it can win. None has had more than a brief chance to take an argument to the public through the media or into the new Commons. No one actually knows what they really think about the big hard issues, yet the contest is being irrevocably moulded all the same. An essential process risks being sacrificed to the abuses of machine politics.

The logical democratic way would be to give the candidates a chance to shine, in parliament and around the country, before, not after, deciding who should run and who gives the party its best chance. The next general election is five long years away. In 2020 the Tory party will be led by a new leader, as may Ukip. Britain’s position in Europe and the future of the union will all look different by then. Choosing the leader now is pretty daft.

The scale of the task, the length of the timescale and the current warped system all point in one direction. Labour should put its thinking head on before it is too late. It should have agreed on an experienced interim leader who commands general confidence to take the party past the Scottish elections and the European referendum and into 2017, while preparing Labour – and its electoral system – for a proper contest between its next generation of leadership candidates in time for 2020. Ideally it should still do this. Someone like Alan Johnson would be perfect for that interim role. His experience, popularity and authenticity would help Labour start to think straight.

Labour is very important for Britain. It needs to do its duty and get this right. It should think, discuss and choose, in that order. Right now it is rushing off in the opposite direction to the one that it needs and its supporters deserve.