Too often in the current Labour leadership debate, people call for Labour to drop virtually all their current policies and standings - which are popular with many people who would contemplate voting Labour. Many feel very strongly that immigration has contributed a lot to our country - but, simultaneously, we have to try and take the pressure off our budget (even though migrants make a significant net contribution to the economy and tax revenue!) as many rightly feel that none should be taking anything at all - until they have contributed to the economy (a two or four-year qualifier would be a half-decent test of this, although maybe it should be based on time in work). This and the much more important reason of immigrants being employed and reducing 'natives'' employment (which can be partially fixed by stopping exploitation of migrant workers) are good reasons why immigration should be restricted.
However, Labour should comprehensively reject the xenophobic argument of restricting immigration because they may be terrorists (very few are) and the fact that people think Britain is no longer 'Britain' as a result (even though we are all immigrants somewhere down the line) because this is not inclusivist or tolerant - values Labour resolutely stands for even in its Blairite Clause IV.
This is essentially what Miliband tried to do - and did well (in theory, at least) - in his term as Leader. He balanced views with expert finesse and held the party together in its defeat. Many call for a rejection of the 'unity' approach. This is not the right way to repair the party. The reason why this approach of Miliband's failed was because the reasons for the policies weren't communicated anywhere near well enough.
Let's take the economy for example - he held that the market was fundamentally broken: the banks needed to be broken up, as did the energy companies, and rail and bus services needed greater public control. The reason was to reduce prices - ultimately - but he simply didn't get this across to the public. He said he would break up the banks - but he didn't say (or clearly) that this would increase competition and thereby force them to offer the public better deals to get service. He said he would give the public sector a greater role in rail - but he didn't say that it was because rail is a natural monopoly, people don't have any choice in company and have to accept the price they're offered, so it may as well be run by the state and have all profits reinvested. He then failed to make obvious to the public why investment needed to be upkept for economic growth and to reduce the deficit. Indeed, Evan Davis ruined him when he gave Miliband the best chance of explaining why he wanted to run a capital account deficit and balance the current account!
He also failed to point out enough that the Tories were not making these pledges and he failed to ask 'why' often enough and then counter their arguments. Miliband was an economic reformer - as even The Economist (not a leftist magazine by any regard!) recognised - and he was an excellent one at that, but he wasn't a performer and this is what ultimately lost him the election. The public didn't understand him well enough and stuck, rather reluctantly, to 'the devil they knew'.
It is very important that Labour doesn't learn the wrong lesson from this. The answer is not to ditch all of Labour's policies and go with the Tories on many key issues because they have a mandate - they have a slim, reluctant, mandate and we must fight for our own large and enthusiastic mandate in 2020. It's also important that Labour doesn't go massively the other way and draw the conclusion that Miliband didn't go far enough: this really would alienate the 'centre ground'! They must unify all the country's inclusivist, tolerant viewpoints into a coherent policy programme and communicate it far better than Miliband did.
[In practical terms, based on the argument made in this blog post alone, the preferences in the leadership election should be Burnham, Cooper, Corbyn, Kendall (Corbyn and Kendall are both off the rails but Corbyn is marginally closer to Labour's pre-election policies). It isn't voting for Continuity Miliband, it's voting for 'Learning From Miliband'
This blog may elaborate on its rejection of Kendall and Corbyn in the future.]