Left wing activists fear they'll lose all influence if they let go of Corbyn, writes Simon Wren-Lewis
But if comments on my recent posts, and personal conversations, are anything to go by Corbyn will be very hard to beat. People are always reluctant to hear that their preferred strategy is not working.
After all it happened to Labour MPs when they believed they had to triangulate to the right to win elections, even after the 2015 defeat.
Now it is happening to Labour party members who still believe they can create a mass social democratic party without the support of Labour MPs. Just as hope will not win out against reality for Labour under Corbyn after the no confidence vote, nor will it do so for Owen Smith’s campaign if he does not address the concerns of Labour members. 
The first thing Owen Smith can do to change this is to acknowledge Corbyn’s greatest achievement: building an enthusiastic activist base for the party. This achievement was only possible because of Labour’s previous failure to do so.
To read some you would think that Corbyn’s support is largely made up of ex-Trots or SWP members, but this is nonsense. It is similar to the support that the socialist Bernie Sanders received, and the rise of new left movements elsewhere.
It is the activist base that Labour desperately needs to help counteract the influence of the media.
One very real reason why this base does not want to let Corbyn go is their fear that without him they will lose all influence. Corbyn’s nomination in 2015 was an act of generosity by some MPs, and members fear with justification that this will not be repeated.
As a result, they believe any prospective candidate from the left will never be on the ballot. When I wrote earlier that the left within Labour would be in a better position after a poor general election loss in 2020 if that loss occurred under Smith rather than Corbyn, this point was quite justifiably made.
Owen Smith could counter this fear by pledging to lower the number of MPs required to nominate a candidate for leader, or by some equivalent means to ensure that members can always vote for a candidate from the left.
Many of those opposed to Corbyn will be horrified at this suggestion, which is precisely why it would be a strong move for Smith to make. My impression is that most Corbyn supporters regard all the 172 MPs as essentially tainted by the antics of the original anti-Corbynistas.
In that sense, my warning that the tactics of this group of overtly anti-Corbyn MPs would completely backfire has proved correct. Many members also see all those MPs as deeply sold on New Labour triangulation, and are reluctant to believe that only a year after the 2015 defeat and Corbyn’s victory, and because of recent events, that election strategy has become history.
Smith should disown this election strategy explicitly, but by making it easier for a Corbyn successor to become leader again Smith will effectively be saying to members that they can always be in a position to prevent any future backsliding.
If Smith wants Labour members to trust him, he has to show that he also trusts them in the future.
The other area where Smith needs to clarify his views is on immigration. At the moment he seems to be living in the same land as some leading Brexit campaigners: saying we need to stay in the EU single market but also that immigration in some areas is too high (although he has also condemned Conservative type controls).
There is a real debate on whether Labour needs to advocate controls on unskilled migration to preserve its working class vote (see my short dialog with Martin Wolf).
As I suspect most Labour party members care a lot more about staying in the single market than they do about controlling immigration, it is important for Smith to signal where his priorities lie.
Smith has already outlined a series of measures on economic policy. There is a lot to discuss and a lot to like here, and I suspect it is not very different from what policy might have been under a Corbyn leadership.
Which suggests an obvious move, which is for him to say that he would offer John McDonnell the opportunity to continue as Shadow Chancellor. (See his Newsnight comments on any offer to Corbyn.)
If that position has already been promised to Angela Eagle in exchange for her stepping aside, then some equivalent offer should be made.
There is a common theme to the first and last points. To defeat the Conservatives, Labour needs to be a broad church. It has to have a strong, effective and largely united set of MPs, but also a vigorous activist base. Remember that Labour membership rose substantially around 1997.
It needs to develop policies that can appeal to both left and right in the party, which has to mean both left and right being involved in policymaking.
If he is to have any chance of winning in September, Smith needs to convince party members that he believes in that and can implement it.
 Just to be clear, I think Labour members should vote for Smith whether he takes up these suggestions or not, because under Corbyn after the no confidence vote Labour are heading for at best a disastrous defeat in 2020 and at worst a split party.
Simon Wren-Lewis is Professor of Economic Policy at the Blavatnik School of Government, Oxford University, and a fellow of Merton College. He has served as an economic advisor to the Labour leadership. This post originally appeared on his blog Mainly MacroLike this article? Sign up to Left Foot Forward's weekday email for the latest progressive news and comment - and support campaigning journalism by making a donation today.