Since Malcolm Turnbull’s successful coup for the prime ministership, the nation has waited to see if he will abandon the unpopular and unfair policies that defined the Abbott years. In large part, he hasn’t. Disappointment ensued.

But those who criticise Turnbull for this do so in error. If we want new policies, we do not need a new leader, we need a new government. And if we’ve lately realised that bad governments can unilaterally pursue damaging and even dangerous policies without any recourse until the next election, we might consider building new protections into our new system of governance as well.

Under Tony Abbott we saw his government’s seemingly insatiable desire to extend its power beyond anything Australia has seen before.

It began with the government set on ignoring the findings of a royal commission charged with investigating the legality of keeping children in immigration detention. It continued with the government refusing to be “lectured to” by the United Nations on its human rights obligations. Next the government determined to put itself so far beyond the reach of the rule of law that it decided to empower its immigration minister to revoke citizenship, a plan for which undermining due process was not only a byproduct, but potentially an objective.

The government determined to build a coalmine despite a successful constitutional challenge. And a royal commission in which a judge had to consider whether or not to recuse himself over a question of bias.

And – under a new prime minister – a pregnant refugee, raped on Nauru, flown back to the island in secret; removed from our courts’ jurisdiction so the government could skirt the injunction her lawyers were preparing to fight for.

The reason the Abbott government was free to do these things is because, in Australia, we permit parliamentary supremacy. Our parliament has the power to make and unmake any law it likes, subject to very few exceptions. The supremacy of our parliament means that we have, comparatively, very little legal recourse to correct injustices in the laws it passes.

It also necessarily extends to the executive. So in Australia, if a government wants to expand its powers through legislation and the powers of its ministers, there is no serious impediment to its doing so.

Nor was there intended to be – the system we inherited was created out of an extended tussle between the power of the monarch and the power of the parliament. Parliament won. The structure that resulted from this struggle was always intended to reflect that victory.

This system has never really worried us. Our country was not born of revolution; we have no real reason to mistrust our leaders. And so we did not need to institute the intricate web of checks and balances required by countries with foundational histories of struggle between the people and all-powerful rulers. What’s more, the system has always worked relatively well. Until now, as we witness our government seeking unprecedented and unchecked powers.

Abbott’s ousting was not enough to stop these alarming recent tactics – strategies that sought to undermine our political system and obfuscate the rule of law. We know that Abbott was partial to the captain’s call, but he did not act entirely alone. Many of his partners in those endeavours – most notably Peter Dutton and George Brandis – retain ministerial positions in our government.

A leadership challenge is not a mechanism for us to keep the government in check, and it should not be treated as such. Quite the opposite – it is the function of a system that vests unbridled power in parliament and, by extension, the party that controls it. This is not the time for Australia to breathe easy.

Our only defence against an unjust administration are our federal elections, and the Abbott era has shown us the time between those elections can feel very long.

This forces Australia to face an unpalatable truth. The reason Turnbull cannot shift on the party’s inhumane policies is because we as a nation chose them. We elected his party based on a platform of stopping the boats and getting rid of the carbon tax, and so on, even if we may not have foreseen the extent of the determination to ignore human rights and to swim against the tide of climate science.

But perhaps the Abbott years and the recklessness that defined them are testament to the fact that some principles should be enshrined beyond the reach of political expediency. Perhaps they are an argument for revising the aspects of our system that make us vulnerable to this breed of government.

The past two years have betrayed the weakness in our system, and in response it may be time to reconsider an Australian bill of rights.

Our constitutional and legal framers and politicians wanted to maintain the integrity of our Westminster structure of parliamentary supremacy. To draft a bill of rights, they reasoned, would be to enshrine a limitation on the power of parliament. It would undermine the legitimacy of our democracy and funnel power away from the representatives we elect.

In theory, this is true. But parliament is capable of misusing this power, and we’ve recently seen how.

A bill of rights framework operates to enunciate and protect the rights and freedoms we consider unassailable, and ensures that no law and no parliament can will these rights away. It does not negate our parliament’s power to write legislation and policy to reflect its decisions about how our country should operate. It simply demands that it makes these decisions without relying on the violation of the basic rights and dignities of any person or section of society.

This path has been charted by almost every other Western democratic nation on earth, and even in two of our own states, without undermining the vitality of democracy.

There are, of course, many different ways in which such a bill might manifest itself – the strict, judicially enforceable structure of the United States’ constitutional Bill of Rights at one end of the spectrum, and the British model, empowering courts only to declare a law incompatible with human rights but not empowering them to strike it down, at the other. Whichever we choose, a clear statement of our willingness to uphold rights would create a key protection that we are currently missing.

It would enshrine in our society a willingness to defend the most vulnerable among us. It would preserve the rights of those not represented by the parties and policies our majority elects. It would also work to protect those who cannot vote but are endangered by our laws more than anyone: those imprisoned and abused in detention centres.

Many opponents of an Australian bill of rights argue that we are already sufficiently protected, because judges across the country in recent years have displayed a commitment to considering international human rights jurisprudence. We refer to the development of a “common law bill of rights”, upheld by Australian courts.

This comes with an important qualification. In a system steeped in parliamentary supremacy, the judiciary’s power to protect our rights is limited. A judge may only act to protect rights when parliament’s intention is sufficiently unclear. If parliament passes a law that explicitly aims to erode our rights, the courts are powerless to stop it. Equally, if a court interprets a law in a way contrary to parliament’s intention, parliament can change the law. All it must do is include an unequivocal intention to set aside rights standards, immune to the act of judicial interpretation, and the courts must fall in line.

Earlier this year, the Abbott government sought to pass a bill to empower the immigration minister to strip Australians suspected of engaging in terrorism of their citizenship. The bill permitted the minister to do so without a criminal conviction, without a trial, or, for that matter, an arrest or charge. The section was titled “renunciation by conduct”.

To avoid interference by courts, the legislation included one key clause: “The rules of natural justice do not apply.”

Natural justice refers, at its core, to our commonly understood notion of the right to a fair trial. All the parliament had to do was draft that single clause in order to legislate it away. In a society underpinned by a bill of rights, we would be protected against this kind of law.

The legal and political issues on the path to implementing a bill of rights are complex but not insurmountable, and the events in our country’s recent memory demonstrate why the question should be vigorously and meaningfully considered.

Parliamentary supremacy may, in theory, amount to an expression of democracy in its purest form. In reality, though, it does little to insulate against a government determined to ensure that “the rules of natural justice do not apply”.