What Would Bill Shorten Need to Pass His Marriage Equality Bill?

On Tuesday, Bill Shorten and Tanya Plibersek announced they plan to introduce a private member's bill to "make marriage equality a reality—without an expensive plebiscite."

Labor is following the lead of Greens senators Janet Rice and Richard Di Natale, who announced Friday that their party will vote against the Liberal Government's proposed marriage equality plebiscite legislation. The Greens back a free parliamentary vote on the issue, and have also announced their own marriage equality bill.

Critics of a plebiscite on same-sex marriage—those who actually support marriage equality—say it will be both expensive, and psychologically damaging to Australia's LGBTQI community.

Moreover, despite polls indicating that a majority of Australians support same-sex marriage, history has also shown divisive campaigns can scare voters away from a Yes vote. The vote on Australia becoming a republic is a key example of this. It failed under the Howard Government, despite polls indicating broad support for breaking away from the monarchy before the country cast their ballots.

A free parliamentary vote on the same-sex marriage issue avoids these pitfalls, which the Greens and Labor no doubt know. But while the marriage plebiscite that formed the basis of the Liberal Party's election platform is looking increasingly unlikely to happen, that doesn't mean that a free parliamentary vote on gay marriage will be easy either.

Following the results of a bitterly-fought federal election campaign, the Coalition have only a slim majority in the lower house—holding 76 seats. Labor have 69 seats, and there are five crossbenchers—the Greens, Katter Party, Nick Xenophon Team, and the independents Andrew Wilkie and Cathy McGowan.

WATCH: VICE Breaks Down the Marriage Equality Plebiscite

Both Wilkie and McGowan support marriage equality, as does the Nick Xenophon team. To pass Shorten's private member's bill, Labor would need 76 votes to pass through the house. This means, assuming all Labor MPs vote together on this issue, they'd only need three more votes.

Those would probably have to come from the Coalition, which isn't quite as impossible as it seems—the Liberals and Nationals are historically more likely than members of Labor to cross the floor and vote against their own party. And there are certainly members of the Liberal Party who support same-sex marriage, leader Malcolm Turnbull being one of them. Though it seems unlikely the PM would cross the floor.

Things might be easier in the Senate, where the Liberal party holds only 30 seats of the 76 seats in the Upper House. Labor have 26, and there's also a motley selection of 20 crossbenchers to contend with—a colourful political spectrum stretching from the Greens to One Nation. But if the nine Greens Senators were to vote with the ALP, they'd only need four more votes to pass the bill. These could come from the three members of the Nick Xenophon Team, and Derryn Hinch—who campaigned on a marriage equality platform, and has stated that he prefers a free vote over a plebiscite.

In the history of the Australian federal parliament, only 15 private member's bills have ever passed into law successfully. But this Bill Shorten's marriage equality vote—depending on when it is introduced and who the ALP bargain with—might just be in with a chance. At the very least, it's likely to embarrass the government.

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