A plebiscite or nothing: that is the message the Coalition will send to anyone asking it to allow a free vote on marriage equality so the reform can pass through parliament now.

It will be the message to lower house independents if they ask for a marriage equality free vote during negotiations to form the next government, or to Labor, the Greens and Xenophon if they dare block plebiscite enabling legislation in the Senate.

“A plebiscite is the only way forward” is certainly the message Tony Abbott signalled just before the election when he said there would be no Coalition free vote for three years or more if a plebiscite was blocked now.

I believe the threat is just bluff and bluster that can easily be argued down.

The election result is the first argument against accepting the political necessity of a plebiscite.

There is now a clear majority of MPs in favour of marriage equality – at least 81 according to Australian Marriage Equality’s count. The number will rise as more seats are decided and more undeclared supporters reveal their position.

Marriage equality could pass tomorrow on a free vote so why bother with an expensive, divisive and non-binding plebiscite, especially when polls show the public backs change and a “yes” vote would have to be legislated by parliament anyway?

The election also failed to give Malcolm Turnbull his hoped-for mandate for a plebiscite. His decision before the election not to outline details of a plebiscite already undermined claims to a mandate.

Voters weren’t told when a plebiscite would be held, what the question would be, what options there would be for answers, whether voting would be compulsory, whether the “yes” and “no” cases would be funded, how respectful debate would be ensured and how the result would be implemented.

When you haven’t told voters what your policy is, you can’t claim they voted for it.

But what really knocked a plebiscite mandate on its head was the election result itself.

Given the high profile of the plebiscite in the run up to election day, it’s not a stretch to say the Coalition lost votes because of its pro-plebiscite stance. They certainly didn’t win any.

This may seem unlikely given polls showing nearly 70% support for a plebiscite. But more in-depth polling shows a different picture. The Melbourne-based Centre for Applied Political Psychology released a poll of 3000 voters a week before the election which showed only 40% support for a plebiscite. This support dropped even further when voters were made aware of the cost of a plebiscite and the fact it won’t be binding.

Looking more broadly than the election, history gives me hope that a free vote, sans plebiscite, is a strong possibility. I have seen gay law reform go from fantasy to fact in a few short months when a Liberal government need minor parties to stay in power.

The best example is Tasmania where homosexuality was decriminalised under a Liberal government that had been previously been a strident opponent of the reform.

Not only did the Liberals drop their blanket antagonism to the change and have a free vote, they applied pressure to recalcitrant upper house members and even stared down a push for a plebiscite on the issue (yes, the idea of a plebiscite on gay rights is nothing new).

The sudden transformation was because the Liberals needed to deal with the Greens to stay in power.

Greens, minor parties and independents should keep this precedent in mind if and when they are negotiating with the Coalition.

History shows that by keeping our nerve, marriage equality advocates have been able to convince the public, then the Labor party, and then a swath of Coalition figures, to back reform.

We can’t let our nerve fail now we are so close.

As public support for marriage equality turns to impatience and the bewilderment of other countries that already have the reform turns to derision, Australian MPs will have no choice but to act.

Even if the Coalition leadership doesn’t see sense and allow a free vote, there will be enough Coalition dissidents who will cross the floor to make marriage equality a reality.

But if you can’t share my hope for a free vote then take heart from Tony Abbott.

Straight after last August’s marathon Coalition party room meeting that came up with the idea of a plebiscite, the then prime minister said that regardless of whether a plebiscite was held:

“I’ve come to the view, I believe this is the party room view, that this is the last term in which the Coalition party room can be bound, although we will definitely maintain the current position for the life of this term.”

If Tony Abbott can imagine a world in which Coalition members can vote how they want on marriage equality without a plebiscite, so can I.