Late Friday, the Obama administration took another step toward following through on its intention to significantly change US detention policy by dropping the Bush administration's favoured description of the Guantánamo detainees as "enemy combatants". What follows in a filing in US district court, however, is disappointingly similar to the Bush administration's assertion of detention authority.

Habeas corpus proceedings inherited from his predecessor likely forced Obama to make this filing before his review of detention policy is completed, and this certainly looks like a work in progress rather than a completed product. But even in that reading, the authority articulated today still needs significant improvement to bring it in line with past practice of the US military and America's obligations under international law.

The Bush administration practically made up the term enemy combatant, as it had no foundation in international law and had almost never appeared in any context prior to 9/11. It has since become synonymous with the lawlessness of Guantánamo, and the Obama administration's symbolic move to drop it from description of its detention authority is yet another signal of its desire to put the disastrous Bush detention policies to rest.

The new Obama position differs from the previous administration's in two other small but important ways. First, it scraps the nefarious interpretation of executive power advocated by Bush lawyers like John Yoo that the president has inherent authority as commander-in-chief to detain virtually anyone, rather relying on Congress' grant of power contained in the 2001 Authorisation to Use Military Force. Second, it requires that an individual must have "substantially supported" the Taliban, al-Qaida or other associated forces in order to be detainable – so the little old lady who donated to a charity only to have it use those funds to support terrorism is now safe.

But other than that, this new detention authority is pretty much the same as the old one. That frustrating reality is likely explained by the timeline of these habeas cases that required the Obama administration to articulate a position on detention authority before its policy reviews had been completed, and, importantly, before it had worked through precisely how and which detainees it intended to transfer out of Guantánamo and where. Attorney general Eric Holder told the court Friday in a separate declaration that the task forces President Obama established to review and develop detention policy will continue to deliberate and will advise the court of any changes in detention policy that would affect the habeas petitioners.

The dilemma the Obama administration faced is that any significant narrowing of the detention authority would likely lead directly to numerous court rulings ordering the immediate release of Guantánamo detainees. The Obama administration clearly intends to work for the transfer or release of a large number of Guantánamo detainees, including many that would be ordered released if the scope of the authority to hold them was narrowed. But it is not realistic to expect them to have worked through all of the real challenges associated with transferring large numbers of Guantánamo detainees in seven weeks when the Bush administration couldn't do it in seven years. It's just not as simple as letting them go.

But buying time only matters if the end result is better than what we have now. The US military had never previously detained as combatants individuals captured outside of a zone of active US combat operations. The Obama administration should return to that practice and limit the military's detention authority to areas in which the president has ordered the US military to engage the enemy, currently Iraq, Afghanistan and the border regions of Pakistan.

That does not mean the US cannot detain suspected terrorists, al-Qaida or otherwise, captured outside those areas, as membership in a designated terrorist organisation is a violation of the criminal law of the US and most likely also of the individual's native country. It just means that the Obama administration should draw the line between military detainees and those in the criminal justice system around the geographical areas where the US military is engaged in combat.

Some are unsatisfied with the pace and substance of change the Obama administration has brought to detention policy. I think that criticism is premature. The trajectory of its policy is clear and was highlighted by the announcement in its first week in office the major initiatives to close Guantánamo, renounce torture and stop extraordinary rendition.

When objections have been raised – on the state secrets privilege, judicial oversight of Bagram or even this action – in each instance, the Obama administration was forced to make filings in court proceedings it inherited from the Bush administration on a timeline out of its control. Advocates for a better US detention policy must continue to push hard, but we must also recognise just how difficult it is to responsibly unwind the complete mess created by the Bush administration.