Not everyone returning from a conflict zone is guilty
Attention has focused on overseas fighters in Iraq since a British national - "Jailer John" - was accused of carrying out the brutal murder of journalist James Foley. The threat posed by radicalised citizens returning from such zones of conflict is alarming. Governments across the globe are grappling for a response.
Ireland is not immune. Gardai are said to be monitoring the movements of up to 30 Irish-based Muslims who travel regularly to the conflict zones in Syria and Iraq. Those numbers are very small. Far greater numbers of Irish citizens served on both sides in the Spanish Civil War. Frank Ryan (of the IRA) and others contributed to the "Connolly Column" in support of the republican cause, while Eoin O'Duffy led around 750 Irish men to serve alongside General Franco. The Oireachtas responded by enacting the Spanish Civil War (Non-Intervention) Act 1937.
But in the current context, are there any lessons for Ireland from other government responses?
In the UK, the Immigration Act 2014 holds out the prospect of the Home Secretary making people stateless. The Act has been criticised for making naturalised citizens "second-class" - the power to strip individuals of their British citizenship does not extend to those who are British-born.
The Irish experience of emigration means that we should, as far as possible, reject distinctions between naturalised and Irish-born citizens. The Irish Nationality and Citizenship Act 1956 (as amended) extends Irish citizenship to any person born on the island of Ireland, from birth, if they are not entitled to citizenship of any other country. We should maintain that position.
The UK Home Secretary has also proposed terror ASBOs. These anti-social behaviour orders would attempt to ban people from joining certain groups.
The Mayor of London, Boris Johnson, thinks the UK should do more. He wants a reversal of the burden of proof for people who travel to zones of conflict. He has been roundly condemned, including in the pages of The Spectator - a Conservative-leaning magazine he used to edit. However, Johnson's proposals are similar to those put forward by the government of Prime Minister Tony Abbott in Australia.
Under the Crimes (Foreign Incursions and Recruitment) Act 1978, it is already an offence, punishable by 20 years' imprisonment, for an Australian citizen to engage in a "hostile activity" in a foreign country. The Act seems specifically designed to tackle the problem presented by radicalised citizens fighting in conflicts such as those in Iraq and Syria.
The problem, according to Australian Attorney General, George Brandis, is that it is not possible to collect the evidence necessary to prosecute individuals. The inability to collect evidence against those fighting in Syria is being advanced as an argument in favour of reversing the burden of proof: everyone returning from specified zones of conflict would have to establish their innocence.
There are numerous problems with Brandis's proposal. It could capture aid workers and concerned family members who visit conflict zones for innocent reasons. Brandis says the new laws will be used sparingly - but "trust us" is never a convincing line. He also argues that travellers with innocuous purposes will be able to raise this as a defence. Proving innocence is not straightforward - there's a reason our law requires the state to prove its case beyond a reasonable doubt.
If Ireland is going to look to Australia, it should ignore Brandis and instead look to the former Independent National Security Legislation Monitor, Mr Bret Walker SC.
Walker is a realist. He acknowledges the threat. He told Australia's ABC: "The idea that a young man could go to Syria, engage in atrocities ... and will come back to Australia and be law-abiding, peaceful and tolerant ... is in my view really silly". But he does not propose statelessness or reversals of the burden of proof. Walker suggests that the security police should be empowered to suspend passports more easily - preventing individuals from travelling rather than responding to the threat of their return.
The threat presented by those returning from foreign conflicts should be acknowledged. But the government should not legislate simply for the act of doing something.
In this situation, intelligence is key. And prevention is better than cure.
Dr Fergal Davis is a senior lecturer in law at UNSW, Australia