Islamic State: Is the US-led coalition working six months on?
Six months ago the US-led coalition launched operations against Islamic State (IS) militants in Iraq, and later Syria. Its results are at best mixed.
While the progress of the jihadist movement has been halted in Iraq, there is a feeling close to despondency about results across the border.
One senior figure in the US-led coalition told me: "We are not going anywhere in Syria at the moment."
A series of recent setbacks underlines this point. The United Arab Emirates (UAE) has quietly withdrawn from strike missions in Syria, with questions emerging about how far any country other than the US is now operating over it.
There have also been revelations about the CIA's failure to develop a reliable proxy force among the rebels fighting President Bashar al-Assad.
And the release of a video showing the murder of Jordanian pilot Moaz al-Kasasbeh has demonstrated all too clearly that IS has created a safe haven where it can act with impunity.
Earlier this week Lt Gen Vincent Stewart, director of the Defense Intelligence Agency, gave the US Congress an assessment that was regarded by many as surprisingly downbeat.
While some commanders have stated that coalition strikes have stopped IS in its tracks, Gen Stewart said the jihadist movement would this year "continue entrenching itself and consolidating gains in Sunni areas of Iraq and Syria, while also fighting for territory outside those areas".
It is in Syria in particular that the political complexities and lack of clear objectives make the military's task harder.
Some coalition partners, such as Turkey and the Gulf states, believe nothing can be done until the US strategy embraces the removal of President Assad - but Iraq, central to the current US plan, supports the Syrian regime.
And when US strikes started in Syria last September, fears that IS might be about to enter Baghdad - and the fact that the government there had asked for foreign help - led the coalition to adopt an 'Iraq First' policy.
To date there have been more than 1,250 coalition strikes in Iraq, and many partners have joined in not just the air action, but the effort to retrain and re-equip the Iraqi army so that it can retake the ground lost last summer to the jihadists.
Having Iraqi and Kurdish forces on the ground has allowed for more effective targeting of strikes in Iraq, and in some places they have indeed won back some territory.
Air attacks have certainly killed many IS foot soldiers, with US Central Command recently assessing the figure at up to 6,000.
Daily reports of a few casualties here or there led one senior US Navy officer I spoke to recently to characterise their progress as working the target "a few bodies at a time".
Privately, though, US officials are downbeat about the chances of the army retaking the Iraqi cities of Tikrit and Mosul - as well as other big centres lost to IS last summer - believing the training effort is going on too slowly and Iraqi government forces are lacking in offensive spirit.
The 'Iraq First' idea aimed to deal with an urgent strategic threat - the existence of the state - and sidestepped the fact that formulating a coherent strategy for Syria seemed impossibly hard.
Now the Iraq front has stabilised, coalition disagreements over Syria have been laid bare. Erasing that frontier between the states is, after all, an important part of the jihadists' ideology and operations.
At first sight, the fact that more than 1,000 coalition strikes have been possible in Syria suggests a similar level of effect as in Iraq.
But many of those attacks were in the area of Kobane - the key Kurdish town bordering Turkey - where, effectively, the allies did have a ground force to assist with targeting. It's been much harder elsewhere.
It is also clear that such missions have dried up from countries outside the US-led coalition.
To date, these countries - all Arab - account for around 7% of the sorties that have used their weapons over Syria.
But only eight of the 81 attacks of this kind have taken place in the past month. So, effectively, having started enthusiastically last September, the Arab element of this coalition has almost shut down.
It has emerged this week that a fear of getting crews captured has played a part in this.
The UAE recently stopped bombing because the US would not move its pilot rescue force from Kuwait to a base in northern Iraq, far closer to IS territory.
That would cut down the response time if another jet went down, but it seems US political sensitivities over putting 'combat boots' into a base in northern Iraq have held them back.
A great many of the myriad problems faced by those running this campaign - from picking up downed pilots or mounting special forces raids, to cutting the number of foreign fighters getting to IS or supplying the Syrian opposition - would ease up if Turkey were cooperating more effectively.
Last autumn, the Turkish government effectively stated its condition for giving that help - US military backing in establishing a large buffer zone in northern Syria. This is a step that would place the allies on the path to confrontation with President Assad's government in Damascus.
The idea of tilting the coalition decisively against President Assad cuts to the heart of disagreements among its members.
Some senior military figures in the UK and France believe the US should actually be doing the opposite - recognising that the Syrian army is the most effective ground force in the country, and cooperating with it.
Iraq, and its ally Iran, have backed President Assad, and would be delighted at such a development.
US leaders, though, are not prepared to enter into any kind of formal alliance with President Assad, holding him primarily responsible for the slaughter in Syria's civil war.
They also know that dwindling cooperation from the Gulf Arab states is not just about pilot rescue.
They have received explicit messages - similar to Turkey's - from the likes of Saudi Arabia, Qatar and the UAE, describing President Assad as the root cause of the Syrian situation and saying his removal must be part of the solution.
Faced with this dilemma, US policy makers are looking at some fresh options, the BBC has learned.
One, for a 'buffer zone lite', would exploit Turkish cooperation in order to secure bases in that country, as well as inserting special forces and rebel training camps in northern Syria.
It does not go as far as Turkey's proposal - which envisaged going up to 90 miles into Syria, taking major centres such as Aleppo and Idlib - but it could get their agreement.
"We have a 'strategy' to defeat IS and a 'policy' to deal with [President] Assad," a senior coalition figure told me, highlighting the mismatch between approaches on different sides of the Iraq-Syria border.
Until the White House resolves its stance on the Syrian leader it will be very hard for those tasked to apply its directive to degrade and destroy IS more effectively.
Newsnight is broadcast on BBC Two, weekdays from 22:30 GMT.