From giving women the vote to repealing the White Australia Policy, the Australian parliament has an amazing history of taking the transformative decisions that make this country so great today.

On issues like economic reform and gun control, Australia was well ahead of its time and we’re still seen as a global leader.

That great history makes it all the more bizarre that we’re on the brink of handballing the next big social change – marriage equality – to an expensive and unnecessary plebiscite, rather than dealing with it in parliament like every other decision that doesn’t need a change to the constitution.

When we elect our MPs, we trust and expect them to make those calls. So why can’t parliament be empowered to make this decision?

There are two problems with a plebiscite.

The first is the damage it could do in the short term.

We’ve already had claims that gay marriage could lead to bestiality, and accusations that businesses that support it are being “totalitarian”. I’ve had people come up to me or write to me saying that they fear worse is to come – their fear is a plebiscite will be open season for most damaging, hurtful language about LGBT people. Given that the rate of depression for gay Australians is much higher than the national average, that’s a serious concern.

This isn’t about giving people time and space for a national debate. Australians have been talking about marriage equality seriously since the early 2000s and we already have the forums for people to express their views on both sides, including the media and the parliament itself. The issue is with using taxpayer funds in a way that could give a platform to the worst kind of homophobic rhetoric – without even binding parliament to the result.

There have only been three plebiscites in Australian history and the last one was the vote on whether to change a national anthem “Advance Australia Fair”. Nobody has a convincing argument for why we need one now.

The second problem is the message calling a plebiscite sends about Australia’s ability to make important national decisions.

Parliament is where we have to agree on reforms in tax, education, environment, industrial relations and immigration policy, as well as debating foreign affairs and the economy. It’s also where we’ve got to come to grips with the social changes that are taking place in Australia just like they are in every other country.

Same-sex marriage isn’t a niche issue. It’s about basic rights and equality – the “fair go” that’s such a fundamental Australian value.

Undercutting parliament by taking away its ability to decide on marriage equality would set a terrible precedent for the next big change we’re faced with, whether it’s an economic choice or a social one.

On the other hand, empowering parliament to vote would solve both the problems of a plebiscite.

It would put a reform that the majority of Australians want to see in the hands of the people we elected to represent us less than three months ago, avoiding a lot of uncertainty and trauma for the LGBT community.

And it would send a strong, positive message about Australia’s ability to show leadership on the big decisions we’re going need to make in this parliament and future ones.