What is the job of a Leader of the Opposition? From the comments of Jeremy Corbyn's critics, you might think that it involves appearing calmly respectable for five years and then winning an election. They insist that Corbyn cannot do this.
What they don't mention is that Corbyn would spend the five years leading opposition to the government - something which his opponents seem reluctant to do.
It is clear that Tony Blair and certain others on the right of Labour would prefer to see Labour lose an election than see it in government under Jeremy Corbyn. In other words, they would rather have a Tory government than a socialist one.
To be fair, not all of them share this outlook but they repeatedly tell us that Labour needs a "moderate" leader if the Tories are to be defeated.
This is outrageously patronising. Those of us who oppose the Tories are expected to sit on our hands for five years, looking forward to the day when Cameron's cabinet of cuts-crazed millionaires is replaced with a government that will be slightly better while leaving the economic system basically unchanged.
I accept that Corbyn would have less chance of leading Labour to an election victory than Burnham, Cooper or Kendall. The establishment - including the right-wing press - would go all-out to attack someone who really does pose a threat to their power and wealth, rather than just wanting to tweak around the edges.
Despite this, I still want Corbyn to win. This is because we need to resist the government now. We need to take every opportunity to defeat their policies. With the Tories continuing their class war on the poorest people in society, we cannot wait five years until we fight back.
I am not a Labour member and will not be voting in this leadership election. But I am prepared to work with people from many parties and none to resist austerity.
The Tories have a majority of twelve. With the help of a few rebellious Tory backbenchers, there is a real possibility of defeating the government at least occasionally in parliamentary votes.
Such occasions are more than symbolic. When John Major's government lost a vote on VAT on fuel, there was a real effect on the lives of many people struggling to heat their houses. When Ed Miliband took his stand against the bombing of Syria, Parliament prevented another use of British troops in acts of mass killing.
Corbyn would lead real attempts to defeat government policies in Parliament. While Cooper, Burnham or even Kendall might do so occasionally, their abstentions in the recent welfare vote reveal their general caution. How much opposition would they really be leading?
More importantly, Jeremy Corbyn is a strong supporter of grassroots resistance to capitalism and war. He has long backed campaigns on the streets, and in communities and workplaces as well as in Parliament and the media. People engaged in protests, strikes and nonviolent direct action could be be broadly united with the leadership of the opposition in Parliament. The other three candidates, on the other hand, would be likely to follow Ed Miliband's lead of distancing themselves from grassroots activism.
We do not have to wait for five years. We can resist austerity and war now. We can work to build a better, more equal, more peaceful world. On the streets, in the media, at work and in the House of Commons, we can resist and change this rotten system.
Many of us - both inside and outside the Labour Party - will keep on resisting the system, whoever wins this leadership election. But it will be a great help to have a Leader of the Opposition who actually leads some opposition.
This post appeared originally at https://symonhill.wordpress.com/2015/08/13/the-mistake-of-corbyns-opponents.