Under international law, a state that has exercised power over individuals at sea by actions such as stopping vessels and boarding vessels is not permitted to return refugees to persecution or individuals to torture.

Those not deemed to be asylum seekers or at risk of torture and who do not have a right to enter the US are then returned to their home country. Some people are returned on the vessel on which they came but most are returned on US Coast Guard vessels, since the US destroys any unseaworthy vessels it stops at sea.

The US Coast Guard transfers any individuals it stops at sea onto its own vessels. If anyone on board the interdicted vessel identifies as an asylum seeker or raises concerns about being returned to torture they are not ''towed back'' but are transferred to Guantanamo Bay, Cuba, where they undergo further processing to determine if they are in fact refugees or are in need of protection from torture. In addition, Cuban asylum seekers are read a statement that alerts them to their right to raise any concerns about returning to Cuba.

Significantly, the US has a policy of taking responsibility for asylum seekers on board vessels it ''tows back''. This is again in contrast with the Coalition plan to take no responsibility for asylum seekers and individuals at risk of torture.

The US signed an agreement with Haiti to permit the return of Haitian nationals in 1981. This agreement has since run out, but Haiti co-operates with the US and accepts boats that have been returned to it. The US also has agreements with Cuba, the Dominican Republic and the Bahamas to accept boats that are returned. By contrast, Australia has no such agreements with other countries.

Admittedly, the US procedures for identifying asylum seekers and individuals at risk of torture are insufficient. Asylum seekers are not given access to legal assistance or the right to an independent review of status determinations, and only Cubans are told of their right to seek asylum.

Despite the inadequacies of the US policy, the Coalition policy is even worse because it does not have any safeguards to guarantee that people at risk of torture who are ''towed back'' would be protected from being returned to their home countries.

There are other aspects of US practice that are unlawful, but are even worse under the Coalition's proposal. For example, under international law, a state can interfere with a vessel outside its waters only if it has an agreement with the country in which the vessel was registered (the so-called flag state). The only exception to this is if a state is rescuing a vessel in grave and imminent danger. The US generally abides by this requirement except in the case of Haiti, with which it has only an informal agreement. As it stands, the Coalition policy appears to interfere with all vessels, in clear contravention of international law.

Finally, as the Coalition has itself acknowledged, the US practice of trying to stop sea vessels has been going on for more than 30 years. Had the boats stopped as a result of the policy, the US would not need to continue this costly practice. After more than 30 years of ''tow back'', the US is no closer to stopping people from taking to the sea in an attempt to enter the country. Nor has the practice of ''tow back'' prevented thousands of people from reaching the US every year. In other words, the US practice has not achieved what the Coalition hopes to achieve. There is nothing to indicate the Coalition would have any more success at stopping the boats than does the US government.

What the US experience has shown is that there is no quick and easy solution to the problem of asylum seekers who are escaping persecution. A bad copy of a ''tow back'' policy that has not worked and is unlawful in the US context, is not going to be the silver bullet the Coalition is looking for.