Socialists in the UK who want to join a political party should join Labour. They should not be uncritical, nor have false expectations, but they should join nonetheless. There are four arguments for this, relating to efficiency, tactics, policy and class.

As far as efficiency is concerned activists who want to elect a left-wing MP will have greater success for the expenditure of less time and energy in Labour. The task of the Labour left is simply to influence the few hundred voters involved in each constituency selection process. To achieve the same in the Greens the left must not only win the selection but then recruit 10,000-20,000 Labour voters to win the seat.

From a tactical perspective it is clear that a moderate national swing from Labour to the Greens could result in no more Green MPs, but dozens of Labour seats lost to the Tories or Lib Dems. This could easily produce a Tory government. Tactically, a vote for the Greens can be disastrous.

These two reasons are important but well-rehearsed. Some would argue that the time and energy, and the short-term consequence of a Tory government, are worthwhile sacrifices for a Green Government (either as majority or part of a coalition) in the future. I disagree. My remaining two arguments seek to demonstrate that the election of a Green Government is not a desirable objective.

There is no reason to believe that, having taken power, the Greens would pursue a left-wing programme. This is my third argument and it relates to party policy. Green manifestos are currently to the left of Labour. But this is not a like-for-like comparison. A party’s policy is shaped by a range of factors, internal and external. The external pressures tend to be right-wing: for instance the need to finance campaigns or to win positive coverage from the right-wing media. As the Green party grows these pressures will intensify.

To counteract these pressures the left relies on internal democracy. But here too the Greens are deficient. The Greens’ party organisation has nothing like Labour’s link to the trade unions so the only ‘check’ on leadership power is the membership. As this grows, the more radical members will surely find themselves in an ever-shrinking minority.

This is not mere speculation. The record speaks for itself. The two most successful Green Parties in Europe are in Ireland and Germany. The former implemented austerity and the latter took the country to war in Afghanistan. Closer to home, the only Green-led council in the UK, Brighton, has slashed jobs and public services. A common rejoinder to this is that the Labour Party fares no better in government. I agree: the left should be critical and put pressure on the Labour leadership. But if a Green administration is not substantially to the left of Labour then why waste the energy needed to elect it?

The fourth and final reason is perhaps the most fundamental. The defeat of the Labour Party by the Green party would be a serious blow to the labour movement and to working-class political aspirations. In the narrow demographic sense, Labour is the party of ordinary working-class people, while the Greens are a party of the middle-class intelligentsia. But more significantly, Labour remains the collective expression of the trade unions. The unions hold just under 50% of votes at party conference, and provide the great bulk of the party’s income.

Even after numerous attacks from the Labour right, the party’s link to the labour movement is still significantly stronger than anything even proposed by the Greens. In fact, the 2010 Green manifesto included a pledge to prevent trade unions from donating to political parties. As it stands, trade unions have little influence in the Green Party and greens have little influence in the unions.

Ultimately, these class interests are the decisive factor. Even if the Greens could take power relatively easily and with no risk of letting the Tories in, and even if there was a guarantee that they would maintain their left-wing programme, to join them would still be a blow against collective working-class politics. One of the greatest tragedies of neo-liberalism is the emphasis on the individual over the collective. Electing a Green government, however charitable and philanthropic its leadership, would undermine the labour movement and the collective organisations of the working class.

Joining the Greens is a tempting option. You are surrounded by people with fairly left-wing politics and you will not be embarrassed by an unpleasant record in government. By contrast, the work in the Labour Party is often not rewarding. You have to engage with unpleasant ideas like dog-whistle immigration policies, the ‘deserving’ and ‘undeserving’ poor, and military adventures overseas. But these reactionary ideas are current amongst the population in general and socialists must challenge them.

If you think that bourgeois democracy can work and that the job of the left is simply to win ideological battles, then join the Greens. But if you are a socialist, and believe that class-struggle is central, then participation in the Labour Party should be a crucial, if uncomfortable, part of your political activity.

  • James McAsh is a Labour Party and anti-cuts activist living in London.  This is the first post in Lab vs. Green – a series debating which political parties progressive activists should get behind in the 2015 UK election.