In the book Ireland Says Yes, an account of the referendum campaign that legalised same-sex marriage in 2015, the authors identified why this was about more than the narrow question of whether gay people could wed.

For young Irish people in particular it was an issue with the potential to transform politics, a chance to directly influence a political system that had failed them.

“They [the yes campaign] needed to persuade younger people that registering to vote was not about continuing politics as usual; they wanted them to realise that the upcoming referendum was a key generational moment where they could become agents of the change they wished to see.”

The Australian government’s proposed postal survey, as ludicrous as it is (there is no need for a public vote in Australia to change the law, as there was in Ireland) may, if it survives a high court challenge, prove to be a similar tipping point.

Conservatives darkly warning of the huge consequences of marriage equality may be right after all. Australians under 30, irritated by middle-age politicians and commentators sneering that “this is not an important issue”, will flex their collective political muscle in a way that could outlast this single issue.

Politics is failing all of us. Trust in our political system is at record lows, and even faith in democracy itself is wavering. Same-sex marriage is one small example of it, but it’s been an educative one. This should have been dealt with by now and hasn’t because of internal party politics and secret deals.

Labor until a few years ago was compromised, with even its atheist unmarried prime minister opposing same-sex marriage for reasons that always sounded hollow. The Coalition government is driven by ideology and personal ambition on this issue and on many others.

I support LGBTI advocates who are fighting this non-binding $122m postal survey. It is demeaning for a minority group that has suffered discrimination throughout our history to be forced to politely ask the majority to judge the equality of their relationships. The “debate” already is painful for many LGBTI people, especially young people struggling with their sexuality.

But if we are to have this survey, if it is foisted upon us, some good may come of it. There would be something uplifting about Australians, particularly young Australians, giving a collective “stuff you” to a political class they rightly feel has ignored them.

For young Australians, let down by my generation on housing affordability, job security, climate change and growing inequality, the silver lining in this mess would be the chance for them to be directly involved in political change and to send a hopeful message about this country.

Recognising and accepting LGBTI people has come a long way in Australia. Views have changed, and changed quickly. Same-sex marriage would be a collective embrace, the strongest symbol we could send that our LGBTI family, friends, colleagues and neighbours are equal, their relationships as rich, varied and messy as those of straight couples.

The Irish debate was unique, but there are lessons for Australia. This was a non-compulsory referendum in a deeply Catholic country to change the constitution to allow for same-sex marriage.

Like here, young Irish people had turned off politics, irritated by its tone and unconvinced that it was dealing with issues vital to them. A study in 2014 found that 30% of those aged under 25 were not registered to vote and were the least likely to vote in elections.

In Australia, where voting in elections is compulsory, 95% of adults are enrolled, but that drops to 85.4 % for those aged 18-24. Almost 280,000 young Australians aren’t on the electoral roll.

I doubt if major political parties care all that much. It is a dangerous drift that should be beyond party politics, but Canberra carries on as though the disillusionment of the electorate was background noise. In Ireland, young people were motivated to vote in the referendum because it went to the heart of the kind of country they wanted to live in. It was personal. If they were not gay or lesbian themselves, they loved someone who was.

In the weeks before the referendum, at least 60,000 new voters registered, with long lines reported at university sign-ups. The overall turnout was exceptionally high at more than 60%.

A study of the results by the Washington Post found that turnout among 18-to-24-year-olds was about 6% higher than it was in the 2011 general election. For other age groups, turnout was typically lower.

As it happened, support for same-sex marriage was so strong among every demographic other than the very old that the referendum would have passed even if young voters had not been so energised. Their enthusiasm made the result emphatic.

Something is stirring here too. There has been little time for an intensive register-to-vote campaign, but the Australian Electoral Commission says that almost 17,000 people enrolled to vote in the week following 8 August, just after the government endorsed the postal survey. An astonishing 215,863 have checked their enrolment details. And this is supposed to be an issue people don’t care about?

There is no age breakdown of these new voters, but it is reasonable to think that a good chunk of them are young, given that they change addresses more than older people and because so many haven’t enrolled before.

Age is a fascinating factor. According to previous opinion polls, almost two in three Australians support same-sex marriage, and that rises to 77% for those aged 18 to 24. Other polls suggest support is even higher. Women support marriage equality more than men. Yes advocates in Ireland focused on men aged 40 to 60 whose support was soft and who were open to no arguments during the few weeks of intense campaigning.

When former prime minister Tony Abbott talks of same-sex marriage being about “political correctness”, or the Australian Christian Lobby claims the children of same-sex parents are the new “stolen generation,” they are talking to these men.

These arguments were raised, and defeated, in Ireland. According to focus groups reported in Ireland Says Yes, the marriage equality campaign was acutely aware that it had to reach these men, not alienate them. “They had a deep-seated unease about cultural change, and feared allowing marriage for same-sex couples might reflect a pattern of social change which, as a participant put it, ‘might snowball’.”

Middled aged voters, particularly men, had concerns about children, “the soft underbelly of the marriage equality issue” as well. It wasn’t good enough to attack such concerns as evidence of bigotry, but to address them directly.

“The best response in all groups was to the argument that all children and grandchildren should be able to marry the person they love and that each son or daughter should have the same opportunity to celebrate their marriage in the same way as their brothers and sisters, irrespective of their sexual orientation,” the book says. The aim was to reach and convince the “million in the middle”.

Middle-aged men might need to be reassured that same-sex marriage isn’t a threat to them. Nothing will change except same-sex couples will marry if they choose to do so. Young men and women already know that and wonder what on earth the fuss has been about.

If the vote happens, they can send that message, no doubt sharing #ivoted photos in front of retro post boxes. Perhaps this is optimistic, but there’s a chance this could give young Australians a taste of their own political power, a stake in our politics that will never again be ignored.

But first, they must enrol or update their address before 24 August – next Thursday.

Young Australians’ disengagement doesn’t help any of us. Their roar would be awesome.