Several of my friends are Labor voters, despite disagreeing with 90% of what the party actually does in office. “Why waste my vote by voting for the Greens?” they ask. “They’ll never be in power!”

For progressive ALP voters there’s a very simple answer to this question: because voting Greens will make the ALP a more compassionate, humanitarian party.

If you vote ALP regardless of how far to the right they lunge, then they know they can ignore you while they chase conservative votes. If you vote Greens and preference ALP, then you tell them that they need to represent progressive views or risk losing seats to the Greens. They’ll precisely two choices then: either adapt by paying attention to what you want and stopping emulating Tony Abbott – or you, along with other progressive voters, will eventually end up electing Greens MPs. (And they’ll hold the ALP accountable to your views in Parliament.)

The reason the ALP keeps lunging to the right is that it thinks its main competition is the Liberals, and it’s trying to appeal to their voters. For the same reason, the more serious the competition it gets from the Greens (by ALP voters abandoning it for the Greens, the same way swinging voters abandon it for the Liberals), the more it’s going to have to compete for progressive votes – which means the ALP starting to actually listen to you! It means the ALP proposing policies with which you might actually agree.

This will not happen if you just vote ALP regardless of what it actually does.

By voting 1 for the Greens and preferencing the ALP, your vote is just as strong at keeping Tony Abbott out – but you also, critically, make the ALP less like him. Julia Gillard emulating John Howard? That’s what you get when you let the ALP take you for granted.

Also, remember: whichever party you vote 1 for gets the funding for next time. By giving your first preference to a major party, you’re helping lock in more of the same policies. By giving it to the Greens, you’re helping to give them real competition.

PS As for “my vote’s not going to make a difference” – it’s going to make just as much difference as every other person’s. You have the same vote as Julia Gillard, or Tony Abbott, or Bob Brown. Pick the one you dislike the most: you can cancel theirs out. If you waste your vote, you’re in effect giving an extra vote to the people you like the least.

Be part of the solution, not part of the problem.