As a nation, Australia needs all the potential policy tools it can muster to deter and prevent the determined illegal immigration that is threatening to swamp our institutions in northern Australia.

If this people-smuggling is not stopped, it will increase greatly, with unknowable consequences.

The opposition has contributed to confusing this debate by demonising the Malaysia deal.

The real criticism of the deal is that it was not likely to work in deterring people-smugglers.

Abbott is giving the government an alibi and allowing it to create a myth that the Malaysia Solution would have been an effective deterrent, whereas its entire deterrent value would have expired once the 800 people had been sent.

However, it would have had some beneficial effect. The truth is that to stop people-smuggling in our north it is necessary to have a variety of measures in place – defence in depth, you might call it. These include offshore processing, temporary protection visas and repelling boats where possible.

But it is surely the height of hypocrisy for the opposition to champion repelling boats and forcing them to sail back to Indonesia, but at the same time object to sending people to Malaysia on humanitarian grounds.

It is the same thing, except that in Malaysia the government would have promised to uphold certain rights for those transferred there, whereas those on boats forced back to Indonesia would not have any extra rights.

By restricting his support for change to facilitate only transfers to Australian-operated offshore detention centres, Abbott is making a huge blunder. He is accepting that anyone who gets into Australian waters has the full right of indefinite Australian protection.

Given how exceptionally difficult all governments have found it to return boat arrivals from Australia, even if established as non-refugees, this protection will effectively be for the rest of their lives.

Abbott is in danger of performing a too-clever-by-half political judo trick on himself, making sure that if he does become prime minister he will not have the legislative and administrative tools to fulfil his pledge to "stop the boats".

It is not good enough for Abbott to enjoy the government's pain.

This is a terrible mistake he is making in disarming the nation – and potentially any future government he runs – in this critical policy area.