It's now three weeks since the Abbott Government introduced a bill into parliament that would see dual-national terrorists forfeit their Australian citizenship.

But is popularity (as evidenced by public support for extending these powers to sole nationals) the rationale behind the pursuit of citizenship-stripping measures, even at the expense of cabinet solidarity? Or does analysis of how the intelligence agencies could use the new powers offer other reasons for their introduction?

It's first worth noting that this is not evidence-based policy; it's difficult to say with certainty what effect it will have on the terrorist threat. What the proposal offers is a potential solution to two inter-linked counter-terrorism challenges: too many targets and the difficulty of securing criminal convictions.

The debate so far has been framed by the activities of the handful of high-profile Australians committing atrocities in the Middle East and threatening to attack Australia. This, we are told, is why the legislation is required. Foreign fighters will return, particularly if the tide turns in the war against ISIS. But it's too early to say how frequently this will occur; Syria/Iraq in 2015 is unlike previous conflicts from which most Western foreign fighters returned.

Still, if returning foreign fighters are the problem, then what is wrong with existing passport-cancellation powers? Any Australian national known to be fighting in Iraq and Syria can be prevented from returning to Australia without notifying the authorities. Foreign fighters cannot slip into Australia unnoticed to conduct attacks.

Stripping their citizenship will not only permanently prevent them from returning, it will also change the rules of engagement. Currently, US air strikes targeting ISIS and al-Nusra fighters cannot 100% avoid Australian casualties, as the recent death of Mohammed Elomar indicates. But as was the case in the UK, this legislation will enable military strikes to directly target ex-Australian nationals located in Syria and Iraq. This won't be a common occurrence (few of the Australians now fighting in the Middle East are of enough strategic significance to warrant air strikes) but it will be an operational possibility. And whether or not this is a fitting punishment, this possibility has been largely (but not entirely) absent from the debate.

However, offences in the legislation – including financing terrorism or a terrorist – show that it is not just aimed at foreign fighters or domestic attack planners. Stemming the flow of funds or equipment to ISIS is important. But it's difficult to argue that financial support justifies 'banishment', or that in doing so you have renounced your right to Australian citizenship.

But even if it did, from an intelligence perspective, these types of offences are often ambiguous. Did you know that the money you sent to your cousin in Lebanon was actually intended for ISIS? Or that the donations you've been making to a charity operating in Syria are being used for terrorist purposes? This ambiguity undoubtedly makes it challenging to find admissible evidence to support your intelligence, but also demonstrates its importance.

Understanding when the powers will be used is therefore critical. The amendment before parliament allows for 'citizenship renunciation' in two circumstances: criminal conviction or 'conduct'.

The challenges of achieving the former in the current counter-terrorism environment are real. The speed and ease with which individuals can leave for the Middle East or conduct an ISIS-inspired attack has resulted in earlier counter-terrorism interventions. And early interventions based on incomplete intelligence reduce the chances of arrests or raids identifying admissible evidence.

The Government says the legislation is required for instances when intelligence shows that an offence has been committed but the intelligence is not shareable in court.

However, the legislation states that the individuals who engage in terrorism-related conduct 'automatically' lose their Australian citizenship. If this is the case, when do the intelligence agencies inform the minister that they have detected such conduct? Do you 'double-dip' if the court doesn't deliver the desired result? Alternatively, why bother with the criminal justice system at all? Surely it's common sense to go straight to the minister if you have reliable intelligence indicating that your target has met the requirement for automatically losing their citizenship? 

How this process works will evolve as internal policy is developed. And in doing so, the intelligence agencies may develop an appetite to use the powers against the full range of permitted targets, not just those highlighted by government rhetoric.

Used sparingly against the most serious targets and threats, preferably post-conviction, citizenship-stripping of dual nationals could deliver operational outcomes and free up resources to focus on emerging threats. But it's vital that these short-term benefits are explained and weighed against the potential long-term impact of widespread use of these powers. What effect will they have on community cohesion or counter-radicalisation efforts? How do we ensure that Australia doesn't 'pass the buck' onto countries less able to cope with the extremist threat?

The debate so far has focused on whether citizenship-stripping is an appropriate punishment for those committing the most extreme terrorist offences. But this does not appear to be the intent behind the legislation, or the only consequence of applying these powers. With limited time for scrutiny and uncertainty over when the powers will be used, it is surely too soon to make them law.

Photo courtesy of Flickr user Tony Abbott.