There is enough polling evidence now to presume that the marriage plebiscite was an utter miscalculation by the conservatives on several fronts. They thought they could defeat marriage equality. They will not.

They thought those most in favour – the young – would not bother voting or were too unfamiliar with the postal system to vote. They were wrong. The young energised, got themselves on the roll and voted.

They thought – 1950s style – that being LGBTI was a matter of shame. They were wrong. They miscalculated the large number of people with LGBTI friends and relatives.

They thought they could muddy the waters with red herrings.

Remember Tony Abbott saying: "And I say to you, if you don't like same-sex marriage, vote no. If you're worried about religious freedom and freedom of speech, vote no, and if you don't like political correctness, vote no, because voting no will help to stop political correctness in its tracks."

They were seen through.

What will the result of this miscalculation be? First, many more young people are on the electoral roll and engaged in politics. Young people are likelier to vote Labor or Green.

Second, a repudiation of do-nothing politics: the politics of being too scared to offend anyone. Like the Aesop fable, they tried not to offend anyone but ended up offending all. The "yes" vote for marriage equality is also a "no" vote for the shock-jock, News-Ltd view of the world that political correctness has gone mad and the world is full of dole bludgers and refugees in Armani apparel.

Third, a repudiation of the myth that if it ain't broke, don't fix it.

The plebiscite will be a game-changer for Australian politics. This is because there is a difference between this and the 1983 miscalculation. In early 1983, Fraser was worried that Bob Hawke would take the Labor leadership and make it harder for the Coalition to win the election that was due later that year. So he called the election for March 5, seven months early. But on the very day he called the election, February 3, Fraser was unaware that Bill Hayden had resigned as Labor leader, so Fraser faced a newly minted opposition leader in Hawke before the honeymoon could wear off.

It was fatal, with no time to repair the damage.

With the marriage plebiscite, on the other hand, Malcolm Turnbull has at least 18 months before he faces an election. If he is agile and innovative, he will make the plebiscite result in his epiphany. But he can take no kudos from the plebiscite, only lessons. The kudos belongs to the Australian people who, having had this unwanted agenda from the right rump of the Coalition thrust upon them, turned the result around.

Times change. This was broke. It needed fixing. The people wanted it fixed and have voted accordingly. If Turnbull does not get that message and deliver it to the right of his party, he and they have had it.

The Turnbull of jobs, growth and security is not enough. That is just what all governments do. Giving priority to jobs and growth has been Australian policy at least since the Vernon report of the 1960s. Priority for national security has been there since at least John Curtin's 1942 turn-to-the-US speech.

So jobs, growth and national security are not a uniquely Turnbull stamp. They are just things all prime ministers do.

What about some 21st century things? Marriage equality is now almost a done deal, no thanks to the Coalition. But what about an energy policy that understands the economic danger of climate change as outlined by the International Monetary Fund, and accelerates the inevitable transition to renewables in a way that puts Australia in a position to take advantage of it?

What about a population policy that understands that Australia in the 21st century is not the underpopulated, insular place of 1945?

What about a 21st century tax policy that takes account of the way multinationals move their capital around to avoid tax, and deals with the 21st century problem of growing inequality?

What about changing tax and population policies to address housing affordability for people who reach adulthood in the 21st century?

What about fixing the 19th century constitution for the 21st century? Surely we can fix the obviously flawed dual-nationality problem for Australian citizens who want to enter parliament. Surely, now that the questions of freedom of speech and religion have been raised during the marriage plebiscite by those champions of human rights, John Howard and Tony Abbott, we can look at a more general bill of rights in the constitution.

Surely we do not need to continue to cling to the 19th century British monarchy. Surely we can recognise and give a greater say to our Indigenous people.

The lesson from the plebiscite must be that Australians are not scared of change and they want their politicians to move with the times and address the changing world.

For Turnbull, the lesson must be not just to change the marriage law and carry on as usual, utterly beholden to the right of his party, but to tell them the game is up. He must risk his leadership now or lose it to Labor later.

And the answer for all political parties is not to change leaders when the polls look bad, but to change policies, even if that means treading on the toes of their financial backers.

crispinhull.com.au