Don't share too early, the parliament ransacked too many people and with the next elections this might be reversed.
They promised too many things too many people and betrayed too many people/
Congrats Australia, you've shot many people in the back and expect a counter-reaction, really great job 
I don't think that'll happen.
First of all the party that passed the Same-Sex marriage laws is actually the right wing party here. They're called the Liberal party but they are the right wing party of Australia, the only other major party is the Labor party and they're left leaning. So if during the next election, the Labor party gets elected, they'll keep it because they've always supported it, and it's unlikely the liberal party will reverse a decision they've already committed to. So unless the One Nation party gets in control (very unlikely considering currently hold only a few seats, and a lot of them have already been fired due to Citizenship issues).
Second of all, before the law passed there was a plebiscite, which was kinda shitty but did show that more than 63% of Australians supported the bill, without any amendments. Not all Australians voted as it was optional (but the voter turn out was considerably larger than any US federal election haha) but all the public polls also show a strong support by the general public for marriage equality, so reversing the decision would be a dangerous one politically.
Third of all, no one was promised amendments by the Bill, I have no idea where you got that from? The idea was proposed by Tony Abbott (who abstained from the final marriage equality bill) and was proposed by some of the campaign managers of the No Campaign, but no minister ever told anyone, or any other MPs, that amendments would be passed. The current bill ALREADY HAS several religious protections that allow, for example, priests to refuse marrying a gay couple, and can allow churches to turn away a gay couple, the amendments were to extend that to [any small business] and civil celebants (IE: people who weren't religious leaders, but in the eyes of the law should not be bound by religion). When the bill was proposed, everyone within the house and senate were totally aware that the bill had no amendments, and if they voted yes to this bill, with no amendments, then the bill would pass, with no amendments, and they still voted yes anyway.
Honestly, I don't know where you get your ideas about Australian politics but you definitely need to rethink your researching strategy.
Topic: Australia voted yes to same sex marrage (Read 2406 times)