LONDON (Reuters) - Turkey, with strong backing from its Arab and Western allies, very much wants Syrian President Bashar al-Assad to step down -- but not just yet.
Under Prime Minister Tayyip Erdogan and his post-Islamist ruling party Turkey has become the main organizing hub for Syria's opposition -- the 260-member liberal Syrian National Council, and the Free Syrian Army, comprising mainly Sunni army defectors.
But across the region and in Western capitals there are fears that Assad's opponents are not ready to take power, and that Syria's ethnic and sectarian mosaic could disintegrate and plunge the country of 22 million into chaos unless a way is found to smooth the transition.
"The key priority is for the opposition inside and outside (Syria) to come together, become a more credible option and include all sects and get their coordination right. Turkey is working on that," a senior Western diplomat in Ankara told Reuters.
"What worries them is that if Assad went today there will be more chaos, more destruction and they don't know who will emerge and they want the opposition to be ready."
The main worry, Syria watchers say, is that what began nine months ago as a civic uprising is turning into a shooting war capable of spilling into a lethal sectarian conflict -- especially as the predominantly Alawite rulers are whipping up the fears of Syria's minorities that they will be crushed by the country's Sunni majority.
This deadly cocktail could then be exported to Syria's fragile multi-confessional neighbors, particularly Lebanon and Iraq where Damascus has fanned and exploited sectarian divisions in the past -- and Turkey itself, where Ankara suspects Syria has already resumed support for Kurdish insurgents in the southeast.
While Ankara has publicly warned Damascus against encouraging the Kurdistan Workers Party (PKK) to step up its attacks, and raised the stakes by joining Europe, the United States and the Arab League in sanctions against the Assad government, most observers believe Turkey is extremely reluctant to take any military action.
"I don't expect any military action by the Turkish government unless there is an international consensus and a U.N. Security Council resolution or NATO operation" says Mustafa Akyol, author of "Islam without extremes: a Muslim case for Liberty."
"They will be more concerned about the Kurdish situation in Syria, because the PKK has a lot of Syrian Kurds in its ranks...and the government believes that Assad is supporting right now the PKK against Turkey."
Sinan Ulgen, a former Turkish diplomat now head of the liberal EDAM think-tank in Istanbul, says Ankara is wary of any rerun of a decade ago, when Kurdish refugees from Saddam Hussein streamed over the Turkish border in the aftermath of the Gulf War, and might now move to create a safe haven or humanitarian corridor inside Syria.
"Turkey certainly doesn't want a repeat of 1991, when 550,000 Kurds crossed the border in a matter of days and we were caught unprepared," said Ulgen. "But Turkey would not do it (a safe haven) unilaterally. It still would need its partners and NATO support, but as things stand there is no reason why NATO would shy away from that."
The US, France, and Turkey are on the same wavelength, said Ulgen, but Turkey would still want a Security Council resolution, and regional as well as NATO support to go ahead.
In a surprising move, Russia, Damascus' longstanding ally, offered the Security Council on Thursday a new, stronger draft resolution on Syria, raising Western hopes of U.N. action following a sharp rise in sectarian killing.
The Western diplomat, by contrast, thinks Turkey would be reluctant to create a humanitarian safe haven because this would commit Turkish troops in Syrian territory.
"They will open their facilities and provide a humanitarian response but I don't think they will intervene, and nor do they want anybody else to intervene," he said. "I don't think Turkish troops want to cross into Syria."
Another Western diplomat in Ankara also doubts there will be military intervention, believing instead that sanctions, which are draining the resources of Assad and eroding his position, will be ratcheted up.
"The most important is to be able to hit the regime and undermine its capacity, which will finally hit is security capability," he says. "There is a progressive crumbling of the regime and the population is progressively losing its fear of it."
Senior foreign ministry officials say they fear Syria could become a new front line in the regional contest between Saudi Arabia and Syria's last significant ally, Iran, or, put in sectarian terms, between Sunnis and Shi'ites of which the Alawites who form the backbone of the Assad establishment are an arcane offshoot.
"The regional entanglement between Sunni and Shi'ite is our biggest worry, that Syria will become a regional war," said one official. "Then you would have Saudi Arabia, Iran, and Iraq getting involved ... and that is something the region cannot withstand."
"Depending on his economic situation we estimate he could last up to a year (but) now that the screws have been tightened, it could be shortened," he added.
Like other Turkish officials, he emphasized the need for an inclusive, non-sectarian opposition platform -- which itself would help shorten the conflict.
"They should have somebody from every part of Syria so that they are as representative as possible, to encompass all the groups in Syria, including the Alawites."
Another senior foreign ministry official added: "There are many oppositions and many factions whereas they have to be representative of all the sects of Syrian society."
"They have to work on it. I don't see them there yet."
Nor does he see as viable another widely touted scenario: an internal coup or palace revolution against the Assad clan.
"I don't see a coup possibility even by Alawites. Assad the father devised a fool-proof system against coups" he said, referring to Hafez al Assad, Bashar's father, who held power for three decades before him.
Some Turkish views are bleaker.
Soli Ozel, a prominent commentator and academic, said: "All the skeletons of sectarian strife have come out of the closet. Once the regime falls I don't see how we avoid a major sectarian conflict if not a bloodbath."
He believes Turkey, which has its own unresolved ethnic divisions with its big Kurdish minority, will not remain untouched by this.
"A country which has sectarian and ethnic faultlines of its own should be more circumspect about where it deploys its forces. I wish we had not crossed the sectarian rubicon in Syria," he said.
Editing by Giles Elgood