VIDEO: Michelle Grattan on Malcolm Turnbull's trouble with marriage equality

Now that Labor has shot down the government’s proposed plebiscite on same-sex marriage, the issue of marriage equality threatens to haunt Malcolm Turnbull’s prime ministership.

Michelle Grattan tells University of Canberra senior lecturer in political science Michael de Percy that Turnbull is under pressure from Labor and same-sex marriage advocates to allow a free parliamentary vote.

“But the Liberal conservatives are making this really a bottom line issue. They will not tolerate a free vote letting the change to the law go through parliament and it would really blow the party up if Malcolm Turnbull did move to that position,” Grattan says.

“At the moment, the issue just simmers away there and maybe nothing will happen until the next election. Then of course the parties will have to put forward election policies and it’s really pretty untenable for the Liberal Party to go again to a poll with a plebiscite, which has become, although initially popular with the community, more unpopular as time has passed.

"So it’s just one of those real burrs under the saddle for Malcolm Turnbull.”