Fifteen years ago, American lawyer Ilya Shapiro wrote a concise and devastating critique of vague statutes.

It must have been missed by those who drafted the latest version of the federal government’s plan to outlaw the online dissemination of misinformation and disinformation.

Just like the first version of this scheme, the revised Bill that has just been presented to parliament has provisions that are imprecise, vague, and – worst of all – subject to expansion and contraction by ministerial fiat.

This is exactly the kind of law that Shapiro warned about in 2009. He wrote that vague statutes give rise to three dangers:

“First, they harm the innocent by failing to warn of the offence,” he wrote.

“Second, they encourage arbitrary and discriminatory enforcement because vague laws delegate enforcement and statutory interpretation to individual government officials.

“Third, because citizens will take extra precautions to avoid violating the law, vague laws inhibit our individual freedom.”

Shapiro, who is director of constitutional studies at the Manhattan Institute, published this warning when he was at another US think tank, the Cato Institute.

He was concerned about how vague laws open the way for the accretion of arbitrary power by governments and their officials – which is the antithesis of what it means to live in a country governed by the rule of law.

Freedom under the law means knowing in advance about the limits on our legal obligations.

That requires precision, not vague laws that are subject to varying interpretations.

Yet vagueness permeates the latest version of the government’s Communications Legislation Amendment (Combatting Misinformation and Disinformation) Bill.

It would turn the Australian Communications and Media Authority into the online arbiter of truth – an authoritarian concept that would be right at home in George Orwell’s book, 1984.

ACMA would gain the power to decide whether digital communications platforms are disseminating statements that meet extremely loose definitions of misinformation and disinformation.

The test would be whether impugned statements are “reasonably likely” to “contribute” to “serious” harm because they are “reasonably verifiable as false, misleading or deceptive”.

That amounts to vagueness heaped upon vagueness. What one bureaucrat might consider to be reasonably verifiable, serious or misleading will not necessarily be the view of others.

The mistake is conceptual: until now the task of assessing public debate and distinguishing truth from falsity has been the responsibility of an informed citizenry, not an all-knowing bureaucracy.

Legitimate restrictions on communication have been limited to particular wrongs with clear limits such as contempt of court, defamation and incitement of violence.

This scheme abandons that orthodoxy and would attack contentious statements that, while otherwise lawful, might be viewed by some as misleading, deceptive or just plain false.

That sort of speech is the price we pay for living in a society where the marketplace of ideas is open to all.

Abandoning that approach and punishing contentious ideas is fraught with danger.

In pre-war Britain Winston Churchill’s strident warnings about the danger of Adolf Hitler’s Nazis might have been seen by his opponents as misleading and dangerous misinformation.

His goal, after all, was to cause as much serious harm as possible to Britain’s pre-war policy of appeasing Hitler.

Yet Churchill’s dissent was tolerated and eventually vindicated. Can you imagine a world in which the law had been changed to prevent Churchill undermining the efforts of the appeasers?

Nobody has a monopoly on truth – least of all public servants who report to a politician.

The first version of this Bill had included harm to the environment as one of the grounds for restricting speech. That is no longer the case.

But that does not remove the threat to the debate over climate change and associated issues such as mining, publicly funded lawfare and the environmental impact of solar farms and wind turbines.

The definition of “serious harm” is just too broad.

ACMA would still, for example, have the power to determine that aspects of the climate change debate are misinformation.

That would be the outcome if it believed some statements were reasonably verifiable as misleading and likely to contribute to serious and imminent harm to the economy.

Normally, organisations are able to determine if they are affected by new laws by either reading the statute or taking advice from lawyers.

That is not the case with this Bill. It has provisions allowing the communications minister – not parliament – to expand and contract the reach of the scheme

The scheme would cover “digital communications platforms” – a term that is defined in the Bill.

But communications minister Michelle Rowland would be empowered to expand the scope of the scheme to cover digital businesses that would otherwise be outside that definition.

Rowland and her successors – not parliament – could simply issue a legislative instrument extending the scheme to cover those businesses.

That is the effect of section 5(7) which gives the minister almost unfettered discretion to determine that entire categories of new digital services are digital communications platforms and therefore covered by the scheme.

More troubling is the fact that section 12(3) would give Rowland and all her successors the power to exempt particular businesses from the scheme – with all that implies for conflicts of interest.

Rowland is an honourable person. But why give any politician unfettered power over the reach of a scheme aimed at limiting freedom of communication?

This Bill is a Trojan horse that would vest the power of parliament in one person.

Some might see this as a way of keeping the law flexible. Others might see it as something that comes close to arbitrary rule.