Michaelia Cash
Attorney-General Michaelia Cash (Image: AAP/Mick Tsikas)

Attorney-General Michaelia Cash has a message for her home state of Western Australia: open your border at 80% vaccination rate or another Clive Palmer-sized legal challenge might come your way.

Cash told The Australian that once those targets were met the state may have less room to defend another legal challenge to its border closures. In November, the High Court unanimously rejected Palmer’s constitutional challenge to WA’s hard border.

Since then, as COVID outbreaks have ripped through the east coast, Premier Mark McGowan has remained adamant about possible lockdowns and continued tight border restrictions — even at those vaccination thresholds. In a long Facebook post yesterday he admitted WA might be a few months behind the rest of the country opening its borders.

McGowan’s position, immensely popular within his state, has put him in the crosshairs of the Morrison government, which wants the country to begin reopening once 70%-80% vaccination targets are reached as part of a uniform “national plan”.

Cash’s threat is just the latest warning from Canberra that WA must get with the program. But will it work?

The last time Palmer challenged the state’s border restrictions he claimed they impinged section 92 of the constitution which provides that “trade, commerce and intercourse among the states … shall be absolutely free”.

But the High Court ruled the relevant sections of WA’s Emergency Management Act were valid on the basis that they were for the legitimate purpose of protecting public health. The importance of protecting health and life, the court said, amply justified the severity of the measures.

However, plenty has changed since November. Now there are two safe and effective vaccines. But University of Sydney constitutional law expert Anne Twomey says that although vaccines change the picture, a challenge to the laws right now wouldn’t succeed.

“If the Commonwealth thinks they can challenge the laws right now, they’re dreaming,” she said.

There could, however, be some scope for a future challenge if McGowan keeps borders shut for longer than necessary to protect public health, Twomey says.

Despite his bluster toward the eastern states, McGowan maintains he will open borders when it is safe and most residents are vaccinated. Cash says the issue of whether the restrictions are proportionate could change once 80% of the population is fully vaccinated. But if WA can still show any restrictions at that point are protecting public health — noting the state’s lower vaccination rates and evidence from experts which the court would hear — it’s unlikely anything would change.

Even then, the High Court’s separate judgments narrowed the grounds for another challenge. Palmer challenged the constitutional validity of WA’s emergency laws, but not the specific orders empowered by them.

“The High Court held that the WA legislation which allows for emergencies was constitutionally valid. As long as the legislation doesn’t change, it’s unlikely to change its mind,” Twomey said.

A future challenge would focus on the administrative rather than constitutional law question of whether the orders to close the borders made under that legislation fell within their scope. Such a challenge would generally start at a lower court. Either way, it would be a long, complicated and messy legal battle.

A political dog-whistle

Cash’s message wasn’t necessarily directed solely at McGowan or West Australians who are quite happy with their hard border and COVID-free lives. It may excite business groups who are antsy to reopen as much of the country as soon as possible, and send a message the government has their back.

When Palmer challenged WA’s laws last year, the Commonwealth initially intervened. Both Morrison and former attorney-general Christian Porter were so confident the challenges would succeed, they spent $1 million supporting them.

Although Cash denied the government would pursue court action, her statements are clearly a coded message of support to any billionaires planning another crack at the west.

Her threat may also excite voters in the locked-down eastern states, who the government’s reductive message of freedom once the country hits vaccine targets is calculated to woo.

McGowan will not realistically keep the border shut forever, and yesterday conceded it might remain only a few months behind the rest of the country in reopening. Despite the Morrison government’s anger, that position is immensely popular in the west. Talk of a legal challenge won’t go down well there.