There is cause for both optimism and scepticism in the news that the US and Russia have agreed a ceasefire in Syria.
On the face of it, one of the world's bloodiest civil wars is about to come to an end — an end to be guaranteed by the two biggest, best armed militaries on the planet. This should be excellent news for everybody, not least the long suffering civilian population of one of the most bombed countries on earth.
The good news first. The Syrian Arab Army and the Kurds as well as their state backers should not fight each other.
The ceasefire announcement probably also forestalls Turkish and Saudi attacks against the government and the Kurds — both of which had either been threatened or were in progress. (The Turks have been shelling the Kurds and Syrian government for a week.)
Likewise, both sides commit to the political process. That includes adherence to the political process mandated in UN Security Council Resolution 2254 (including cessation of hostilities and a process leading to democratic elections).
Equally, the parties will allow aid to reach beleaguered areas. They also agree that they will work for the release of detainees.
These benefits cannot be underrated. While civilians have been used as a political football by all sides (both while there and once they have fled as refugees), there is no doubt they have been suffering. Once bustling, lively and ancient cities have been bombed, mined and booby-trapped. The inhabitants have been besieged, often for months, with limited access to food and water while living in the crossfire.
Even those living away from direct battlezones have been attacked — in the last days, dozens have been killed by car bombs in Homs and Damascus. Thousands have fled, meeting a mixed reception in places from Turkey to Nauru (from where three asylum seekers from Aleppo imprisoned by Australia have just found refuge in Canada).
So far so good.
So what could possibly go wrong?
Well, quite a lot. For a start, who is covered is unclear and open to a good deal of wrangling. The ceasefire covers 'any party currently engaged in military or paramilitary hostilities against any other parties other than 'Daesh', 'Jabhat al-Nusra', or other terrorist organisations designated by the UN Security Council'. In addition, persistent violators of the ceasefire will be treated as 'terrorists'.
The question of who else will or will not be treated as a terrorist group is much harder to answer. Way back in September, General Austin told the US Congress that the US attempt to train 'moderate' rebels with ideals more in line with the US than those of Al Nusra or ISIS had yielded 'no more than four or five' who were still in the field.
Since then, however, the US' standard reason for not supporting the Russian efforts (leaving aside the bloody nature of both great powers' air campaigns in Syria) is that they target 'moderate rebels' rather than ISIS or Al Nusra. (The Russians have taken the ethically dicey, but consistent, line that Assad is the best of a bad lot.)
As a result, it has been painfully clear that both the US and Russia will continue to differ on who is a moderate rebel and who is not.
In addition, even assuming that any party to the Syrian civil war is 'moderate', the ever-shifting quagmire of rebel alliances means it is almost possible to avoid supporting a 'non-moderate' rebel group even if you put your money on someone else.
In this way, for example, by supporting Jaish al Fatah, the US and their allies have been channelling arms to Al Nusra (one of its affiliates). Worse, some of the 'vetted, moderate rebels' have been funnelling their weaponry direct to the Al Qaeda franchisee.
Thus, it will be very difficult to determine whether or not one of the rebel parties to the ceasefire is acting in self-defence or is simply a terror group with a change of uniform or badge.
In addition and, to some extent, lying behind these conflicting allegiances is the fact that superimposed on the Syrian civil war is an ongoing cold war and proxy conflict between Russia and the US. As in the old Cold War, each has come to see geopolitics in terms of a zero sum game — what's bad for them is good for me and vice versa.
It is this questionable logic that led to the rise of entities like Al Qaeda in the first place as great powers found themselves rearing and riding tigers which they could not dismount. Only time will tell whether the great power guarantors of the ceasefire are more interested in peace on the ground or in gaming the system for their own perceived short term gain.
Aside from these long term issues, there is the short term question of what happens in the meantime. The ceasefire only takes effect in three days. That would seem to guarantee a scramble for territory and a consequent intensification of the fighting within the next three days as each party to the conflict and its backers muscle in to secure as good a position as possible pending the ceasefire.
In summary then, while the ceasefire can only be an improvement on the current situation, it will take a fair while to tell whether it will make a genuine difference or whether it is yet another false dawn.
Justin Glyn SJ is studying for the priesthood. Previously he practised law in South Africa and New Zealand and has a PhD in administrative and international law.