Because the Liberal Party of Australia (our main conservative party - the name harkens back to the old idea of classical liberalism, not the left wing ideas the progressives have tried to hijack the word 'liberal' for) is a party founded on individual freedom, as a matter of longstanding policy, a backbench MP (that is, one who does not hold any government office, but simply represents their constituency in Parliament) is always free to vote as they wish without consequences, even against party policy - but those who hold office as Parliamentary Secretaries (junior ministers), Ministers, or Cabinet Ministers must vote the party line unless a vote has been declared "free" or face resignation, or being sacked. The Prime Minister is making it clear that he expects the Ministers to hold to this principle - and if they don't, they will wind up going to the backbenches themselves.
I expect some backbenchers will cross the floor, as Warren Entsch has said he will. I'd be surprised if any Ministers did. Overall it is almost certain that not enough will vote with the opposition to force gay marriage through. For now the line will hold.
Hang tough mates!
IMHO
Marriage is the union between a man and a woman in matrimony. A very very simple concept. Gays calling themselves married are of course doing it wrong.
Good for them.
NO POOFTAHS!
Shorter PM Abbott: “Give them an Entsch, they’ll take a mile.”
Common sense prevails in Australia! Alas, not here in the U.S.A. Gays can create their own contracts with each other - just don’t call it marriage. No one is stopping them from riding a bull if they want.