When law students are asked to cite examples of legislative ineptitude, they now have two perfect case studies.

After last year’s High Court ruling in the case known as NZYQ, the government was caught flat footed and released people from immigration detention with inadequate oversight.

It paid a terrible price for that lack of preparation. But that was just the start.

Once it had the benefit of the High Court’s reasoning in NZYQ, it would have made sense to draft a response that took account of the court’s ruling so it did not meet the same fate.

After all, when it comes to questions like the separation of powers, the court has the final say, not the government.

It is therefore astounding that a key part of the government’s legislative response to that decision – curfews and the wearing of ankle bracelets – has now been struck down for exactly the same reason.

It’s as if the parliamentary draftsmen had been instructed to ignore the risk of legislative invalidity and prepare new rules that looked so tough they would silence the government’s critics.

The latest ruling, in a case known as YBFZ, should not be seen as an example of activist judges siding with foreigners who have no business being here. 

Both rulings, NZYQ and YBFZ, are examples of the court striking down improper breaches of the separation of powers by governments.

These decisions do not mean the judges will always be opposed to curfews and ankle bracelets for foreign criminals. It simply means that laws imposing punitive measures should leave the judiciary as the decision-maker. 

Instead, the government’s rules on curfews and ankle bracelets left the minister for immigration as the sole decision-maker. This is at odds with the community safety supervision order regime in the Commonwealth Criminal Code.

The leading judgment in the latest case makes the point that these supervision orders can be made by state and territory Supreme Courts on application by the minister for immigration.

In retrospect, that is the approach that should have been applied to curfews and ankle bracelets.

Instead of imposing these measures only on those detainees who are proven in court to be dangers to the community, the government seems to have legislated in a state of panic.

It accepted demands from the opposition and imposed these requirements on all former detainees unless the minister is persuaded to the contrary.

The government seems to have known it was on dangerous ground. This might explain why it paid legal costs and surrendered to several former detainees early this year to prevent their legal challenges from reaching the High Court.

The result began to resemble arbitrary rule: some former detainees who had been released into the community wearing ankle bracelets were relieved of that obligation while others were not.

The decision striking down the rules on curfews and ankle bracelets would have come as no surprise to anyone who was aware of the critique of this regime by constitutional lawyer Anne Twomey.

Because ankle bracelets were the default position, she warned in March that this suggested the purpose was punitive rather than a protective measure based on risk.

“And as we all know, a punitive purpose leads to constitutional invalidity,” she said on her YouTube channel, Constitutional Clarion.

The leading judgment put it this way: “The impugned conditions are a form of extrajudicial collective punishment based on membership of the class.”

This was a bad law, enacted in panic, with insufficient regard to the separation of powers.