ANKARA/ISTANBUL - When Washington takes its bombing campaign against Islamic State fighters into Syria, the most it can probably hope for from one of its closest allies in the region will be grudging consent.
Turkey, a NATO member with a big US airbase and long borders with both Iraq and Syria, has made clear that it is still unconvinced by US President Barack Obama's plans to bomb Islamic State fighters in two of its neighbours.
While Washington won backing last week for a military coalition from 10 Arab nations - Egypt, Iraq, Jordan, Lebanon and six Gulf states including rich rivals Saudi Arabia and Qatar - Turkey attended the talks but did not sign up.
President Tayyip Erdogan and Prime Minister Ahmet Davutoglu, architects of a foreign policy which envisages Sunni Muslim Turkey as a regional power, are reluctant to engage in action they fear could strengthen their enemy, Syrian President Bashar al-Assad, and exacerbate sectarian tensions in Iraq.
"It's a very complicated balancing act. Turkey is trying to satisfy its US partner without extending full collaboration. They will come under intensifying pressure but will find it very difficult to block US strategy," said Fadi Hakura, Turkey analyst at the London-based think-tank Chatham House.
"It's a coalition of the unwilling and the apathetic. Turkey and most Arab countries supposedly part of this coalition are deeply sceptical of US intentions in the region." Turkey's role is likely to be limited, US and Turkish officials say, to stemming the flow of foreign fighters crossing its borders, helping cut off Islamic State's finances and providing humanitarian and logistical support.
There are no plans, Turkish officials have said, to allow the US airbase in the southern town of Incirlik to be used for air strikes. Pro-government newspapers have welcomed Ankara's reluctance, drawing parallels to 2003, when Turkey's parliament rejected a US request to use Turkish territory to invade Iraq.
"Turkey has to play the long game, and right now the strategy disclosed by the US government does not give confidence that the region will be stabilised," said Sinan Ulgen, head of the Centre for Economics and Foreign Policy Studies in Istanbul.
"Just hitting ISIS won't solve anything ... The recent history of Western intervention has amply demonstrated this. Look at where Libya stands today, at where Afghanistan stands today, at where Iraq stands today," he said.
"Islamic State is actually a bigger threat to Turkey than to the United States, so there is every incentive for Ankara to be part of this coalition. But right now there is no big overlap about its strategic direction."
When Islamic State fighters surged into northern Iraq in June, they captured 46 Turkish hostages in the city of Mosul, including diplomats, soldiers and children. Turkish officials say the plight of the hostages is one reason they are reluctant to sign on publicly to a campaign against the fighters.