Legal experts back Michaelia Cash on state borders

Constitutional law experts have backed ­Michaelia Cash’s warnings that the premiers’ powers to shut borders could diminish once 80 per cent of Australian adults are vaccinated.

Former Australian Catholic University chief and constitutional law expert Greg Craven. Picture: Jane Dempster

Constitutional law experts have backed ­Attorney-General Michaelia Cash’s warnings that the premiers’ powers to shut borders could diminish once 80 per cent of Australian adults are vaccinated against Covid-19.

The High Court last year ­upheld Western Australia’s hard border – after a legal challenge by mining billionaire Clive Palmer – on the grounds it was a proportionate public health response to the pandemic given there were no available treatments or vaccines for coronavirus.

Senator Cash caused a political storm this week when she told The Australian that achieving an 80 per cent adult vaccination rate would shift the legal arguments around the proportionality of state border closures.

Constitutional law expert Greg Craven – a former Victorian crown counsel and former vice-chancellor of the Australian Catholic University – said the vaccine rollout had changed the arguments.

“Cash is right and she’s not the only person who’s saying it,” he said. “If you look at the Palmer vs WA case, it rests on what is proportionate and reasonable. If Covid-19 disappeared tomorrow, would closing state borders be ­appropriate? Absolutely not. So it will be up to the court to decide if there are enough vaccinations to make it a proportional response.

“I suspect the balance of the ­arguments that were presented to the High Court has shifted, and the court may have certain regrets about the initial decision which has very cheaply sold the federation down the drain.”

WA Premier Mark McGowan has reacted angrily to Senator Cash’s warnings and accused her of encouraging Mr Palmer and others to challenge border closures.

University of NSW constitutional expert George Williams said while the legal arguments on border closures had shifted, it could take months to resolve and federal parliament had the power now to enshrine the national plan vaccine thresholds in law.

“The High Court will go on a fact-finding mission, and probably refer the matter back to the Federal Court as it did last time, to gather the evidence on proportion … it would take months,” he said. “The federal parliament – under its constitutional powers of quarantine and the external powers act – could legislate for free movement across states and the national plan now. This should not be left with the courts.”