Poetry, WH Auden once wrote, makes nothing happen.

The same might be said of journalism.

Auden understood himself as defending (rather than attacking) a form he loved, distinguishing what a poem might do from what could and should not be demanded from it.

Similarly, the expectations of journalism have never been higher, with many liberals convinced that almost all the depredations of contemporary politics could be prevented if only the press put its mind to it.

Yet, in reality, the vacuum that makes the media seem so important also limits what even the best journalism can do.

Take the tenacious reporting that pursued Angus Taylor for using an allegedly forged document to smear Sydney’s lord mayor, Clover Moore.

Here was a potential scandal dissected forensically across sites like this one – and what was the result?

A few weeks ago the AFP declared that Taylor’s actions would not be investigated because of “the low level of harm and the apology made by the minister”.

The media spotlight directed at Taylor raised questions of potential wrongdoing for all to see … and then the authorities shrugged and moved on.

Similarly, with his barely disguised contempt for journalists quizzing him about the sports rorts saga, Scott Morrison shows that he understands perfectly well what the media can and can’t do. If he stonewalls and blusters for long enough, even the most determined interviewer must go to the next question – and then Morrison can repeat the tactic until the issue goes stale.

Many commentators have contrasted today’s political impunity with the story of Bob Hawke’s special minister of state Mick Young, who famously stepped down after he and his wife failed to declare a stuffed Paddington bear in their luggage after an overseas trip.

As the Age’s Tony Wright says, Young’s conduct would be “unimaginable now”.

Yet no one would suggest that the media was somehow more effective back then.

On the contrary, politicians in 1984 faced much less scrutiny than they do in the age of social media and 24-hour cable.

The Paddington bear incident instead illustrates the importance of a political culture that no longer exists.

Young left high school to work as a shearer and roustabout in South Australia before becoming an organiser with the Australian Workers’ Union, back when something like half of the entire workforce belonged to a trade union. He rose up through the ranks of a Labor party that (like, in fact, the Liberals) possessed a functioning branch structure.

You couldn’t imagine any of that today.

Not only has union density sunk to an all-time low, the political parties that once boasted huge memberships have become empty shells. Much the same might be said about the traditional churches, social movements and community groups.

There’s no mystery as to why.

As Elizabeth Humphrys documents in her recent book on neoliberalism and Australia, the free market reforms implemented by Hawke and Paul Keating (and then extended by John Howard) devastated the labour movement – and, eventually, civil society more generally.

Today, we’re expected to relate to politics (and everything else) as atomised consumers (rather than members or participants), a mode fundamentally incompatible with the traditional values of civil institutions.

In the past, the existence of stable mass organisations gave some force to political conventions like “ministerial responsibility”, partly because traditions need institutional memory to persist but also (and more importantly) because those organisations provided the public with mechanisms (however imperfect) through which leaders might be disciplined.

The density of civil society in the 1980s meant that political scandals could not be shrugged off in the same way that they can be today, since a much larger proportion of the population had some organised engagement with public life.

It’s that engagement that gives journalism heft.

Think, for instance, about the role played by Carl Bernstein and Bob Woodward from the Washington Post in bringing down Richard Nixon.

As Ken Burns and Lynn Novick write, “we often forget that the [Vietnam] war and the Watergate scandal were inextricably intertwined”, with the highly politicised culture created by the peace movement keeping the Post’s revelations alive and eventually forcing Nixon’s resignation.

The contemporary American context could not be more different.

“I could stand in the middle of Fifth Avenue and shoot somebody and I wouldn’t lose any voters,” boasted Donald Trump in 2016.

In that claim, you can see the problem facing journalists everywhere.

No Bernstein and Woodward-style investigation could publicise the US president’s bigotry, venality and incompetence as thoroughly as Trump does himself.

Everyone knows who Trump is and what he represents – and yet that knowledge, in and of itself, changes nothing.

It’s not enough to know. You need to be able to act – and, today, most people feel that they can’t.

A widespread public alienation from the political process gives Trump (and the growing number of Trump imitators) tremendous latitude – a latitude that, in turn, fosters more public alienation.

The Roman senator Tacitus one explained how “crime, once exposed, has no refuge but in audacity”.

Today, that’s the default mode for a political class able to brazen out almost any scandal, safe in the knowledge that no particular penalty attaches to exposure.

That’s not to excuse those journalists who’d rather be lapdogs than watchdogs.

We need, more than ever, reporters prepared to make public what the powerful would prefer concealed.

But, even more urgently, we need to rebuild a popular agency – for, without it, the most shocking exposés will fall completely flat, again and again and again.

• Jeff Sparrow is a Guardian Australia columnist