Donald Trump, as a destructive force, hit the political system of the United States with a resounding bang. But perhaps liberal democracies can also be brought low by means of a long and slow deflation.

Institutions may not collapse overnight, just gradually cease to function as they should, and from there cease to attract assent or faith. Elites may not, as they have in the United States, begin howling in unison at the moon about Russian conspiracies, but instead become incrementally more self-serving, more isolated, and less attuned to their ostensible constituencies. Governing ideas may not enter any sudden crisis, but slowly lose any relation either to reality or a broad, popular consensus.

In these cases, the telltale signs may be found as much at the margins as the centre, as slow cracks infinitesimally broadening, day by day, slowly but inexorably weakening a structure that everyone assumed would last forever.

And guiding assumptions, beliefs, and the whole fabric of common sense that binds any political system may itself be stretched and frayed until it is no longer fit for purpose.

Australian democracy right now may be more vulnerable than many care to admit. One reason is that the branch office mentality of so many politicians often leads them to assimilate and ape American trends. The usual suspects have been flaunting their Trump fandom, but others may come to see his victory and his politics as something to be more closely emulated.

More serious, though, are multiplying signs of a kind of structural rot whose sources are internal.

Twinned national headline political stories – Centrelink’s debt woes and the apparently common abuse of parliamentary entitlements – suggest that our political elites are at least as decadent as their American counterparts.

The minister for human services, Alan Tudge, has defended the mechanised but indiscriminate collection of Centrelink debts from citizens because of the money it will save. This reveals how, at the highest echelons of our political life, the idea is now embedded that the primary function of such institutions is not service, let alone welfare, but discipline.

On the other hand, Malcolm Turnbull’s colleagues – some of them ministers – have freely availed themselves of public largesse, allegedly using travel allowances to scout for investment properties and attend polo matches.

This systematic lowering of expectations may be a greater long-term danger than its immediate fruits.

And yet somehow this twinned scandal doesn’t vibe in the way it once might have. It has kindled genuine and widespread public outrage but this seems disconnected from the political system. Sussan Ley resigned as health minister and Turnbull introduced changes to MP entitlements – a year after recommendations were made to overhaul the system – but we’ve been here before. Who expects any more fundamental changes? Who doesn’t think we’ll arrive at this point again?

Maybe Steve Cibo is right. Perhaps this kind of catastrophe – with all its serial incompetence and hypocrisy – is now what we now expect. Perhaps we have become accustomed to it. As political theorist Jodi Dean wrote about the mass global protests against the Iraq war, which were similarly ineffectual, “the message was not received. It circulated, reduced to the medium.”

This systematic lowering of expectations may be a greater long-term danger than its immediate fruits. The placeholder currently occupying the Lodge – the latest in a sequence stretching back over a long decade – is a living reminder how difficult it is to draw a bead on a government’s short-term failures when they have no discernible long-term projects in mind.

Everywhere, there is a sense that no one can imagine any higher task for government than managing an eternal present. As the Great Barrier Reef is pitilessly bleached to the colour of dead bones, Queensland’s government has been bending over backwards to accommodate a massive new coal mine.

The inevitable consequences of fostering a dirty and retrograde industry, and the long slide in its price, are never allowed to intrude on the present. That’s because our politics seems incapable, for now, of imagining any future that differs, for good or ill, from whatever is given.

If the centre of our politics is such a moral and intellectual vacuum, we can’t be surprised when all kinds of detritus washes in from the fringes. A One Nation candidate who believes that the world’s media fakes refugee photos is, in any case, not so jarring alongside the waving through of Senate inquiries into halal food, or the presumption of guilt that underpins the bipartisan commitment to keeping refugees in offshore prisons.

The politicians who posture in opposition to Trump’s wall while supporting the maintenance of our version are just another indicator of the hollowness that reveals itself wherever we knock.

They’re all artefacts of drift, of an absence of principle and imagination. Of something that may never manifest itself as a catastrophe, but instead as a steady and remorseless unwinding. A slow leak that can only be patched with belief.