Everywhere you look, democracies are reeling. Brexit and the election of US President Donald Trump slammed home the deep shifts under way. In Austria, The Netherlands and France voters went to the brink of electing far-right candidates, and in The Philippines they did. Feeding this backlash are outside meddlers to whom democracies seem newly vulnerable. US intelligence services believe Russia made a concerted effort to influence their election and France’s President has condemned similar efforts there. Britain and Germany are on red alert as they head to the polls.

The search for answers to this global wave of discontent often zeros in on rising inequality, voter alienation or changing demographics. But is there another shift we have missed, a shift that amounts to a fundamental restructuring of how democracy operates?

Hints of the titanic proportions of this restructuring were on full display this week when more than 25 media bosses flew into Canberra to implore Malcolm Turnbull to change the way their industry is regulated. Early last month, Fairfax Media announced yet another round of staff cuts and a foreign equity firm started circling. A research team tracking the Australian media says more than 3000 journalists in mainstream media have lost their jobs in the past five years.

The usual reaction to the mainstream media’s decline is to point to the tech giants that have destroyed the industry’s business model. Facebook and Google have poached the advertising revenue that used to pay for journalism. Adding insult to injury, under Facebook’s all-embracing newsfeed, rantings of the extremes and fabricated stories from Russia are given equal weight to the fact-checked work of professional journalists.

But this superficial analysis misses a much more important second order consequence of the tech giants’ destruction of the mainstream media. It misses the attack on democracy itself.

Many years ago, a PR professional told me she distilled her core advice to those wanting to shape the political agenda to two words, “print leads”. Her explanation was simple and intuitive.

Newspapers arrived on the breakfast tables of politicians and radio and television producers at 5am each day. The rest of the day’s news stories were largely reactions to what was in those papers. Radio broadcasters would use them as fodder for their stories. Politicians would react to the claims made in the papers and on radio. Television journalists would interview politicians and experts for their views on the papers’ most striking stories.

Before Facebook and Google had laid waste to the media landscape, that advice was sound and logical.

Today, it seems from another era. As we all know, news breaks constantly. Nobody waits for the morning papers to learn of a terror attack in Manchester or an election result in France. We get the news delivered to our smartphones the instant it occurs.

If the only thing Google and Facebook had done was help us all get information faster, who could complain? But the unforeseen consequence of their rise is far more significant.

Thomas Carlyle attributes the term fourth estate, referring to the print media, to 18th-century statesman and philosopher Edmund Burke. According to Carlyle, “Burke said there were Three Estates in Parliament; but, in the Reporters’ Gallery yonder, there sat a Fourth Estate more important far than they all. It is not a figure of speech, or a witty saying; it is a literal fact. Printing, which comes necessarily out of Writing … is equivalent to Democracy.”

The term fourth estate captures the idea of the print media existing alongside the executive, legislature and judiciary, supervising them and serving the public good. The symbiosis between newspapers and democracy goes back to the start of modern democracy.

The relationship has been tense from the start, and debates about the media’s influence and journalistic ethics are perennial. Second US president John Adams had notorious fallings out with the print media and infamously signed into law the Alien and Sedition Acts, which allowed several publishers, whose coverage he did not appreciate, to be imprisoned.

However, as democracies consolidated and spread, the fourth estate became intrinsic to our system of government. Often its role is simplified to conveying information to the public. Yet that misses a far more important point.

Journalists do not just transmit information. They decide what information to transmit. And herein lies their truly important function in democracies: stewardship.

Journalists traditionally have set the parameters of all political debate. When they report on potential changes in prime ministerial leadership we, the public, are not presented with the merits and shortcomings of all 76 Coalition MPs and left to form a consensus among ourselves as to who we like most. What we get are the two or three contenders journalists deem serious.

Similarly, journalists decide on the acceptable standards our representatives must uphold and doggedly pursue any breaches of this unwritten code. Thus, we read almost nothing of extramarital infidelities committed in Canberra but are sure to hear of any misspending of taxpayer money.

The same thing happens with public debates. Journalists decide the acceptable limits of public discourse and those who veer outside these bounds are ignored or attacked until they are removed or resign. Thus, we do not hear debates advocating genocide.

To some this may sound like censorship or paternalism, but what it really is is civilisation. If we want to live in peaceful and prosperous societies, we can’t afford to give a prominent and endorsed voice to those who advocate violence or the like.

Since the advent of modern democracy, journalists and the organisational structures around them have not just reported information. They have set the shortlist of political candidates who will get our attention and therefore be elected. They have regulated the acceptable bounds of what those elected representatives can say to us. And they have arbitrated the values and standards our leaders are held to. They have been, in short, integral to the way our democracy works.

While many factors are at work, the breakdown in the mainstream media’s traditional stewardship role appears to be wreaking havoc in democracies. Trump managed to manoeuvre himself from joke candidate to winner of the Republican primaries, in part through his ability to bypass the mainstream media and speak directly to disaffected voters on social media. His presidential bid was aided by fake news and Russian influence campaigns amplified by automated bots that created an artificial impression of wider support for his views. One study of Facebook users’ engagement with mainstream and fake news in the lead-up to the US election found fake news engagement surpassed that of mainstream news just before voting day.

Democracies are in crisis mode, trying to figure out how to protect themselves against Russian-style online influence campaigns that have been enabled by the destruction of the mainstream media’s previous stewardship role.

Of course, there is no going back. But as the Senate prepares for its inquiry into the future of public interest journalism, it should look beyond the narrow question of Google and Facebook’s effect on individual news outlets and consider their impact on our democracy and how we best protect it.

Fergus Hanson is head of the International Cyber Policy Centre based at the Australian Strategic Policy Institute.