Leading article: It is time for Turkey to take the lead on Syria

Here was Ankara’s first serious test as a regional power: it is a test that it has so far failed

Outrage over the Houla massacre remains high, but there is also a growing sense of despair that nothing effective is being done to prevent its repetition. Almost every day, evidence is produced of fresh killings by Syrian government-backed death squads that bring the country closer to all-out sectarian civil war.

The expulsion of Syrian diplomats this week was a purely symbolic gesture, and the economic sanctions in place are more likely to hurt ordinary Syrians than their leaders. And although Russia shows signs of becoming weary of paying an ever-increasing political price for its support for Syria, the stalemate in the UN Security Council is also unlikely to change for the moment.

But perhaps the most surprising aspect of the impasse is Turkey's failure to act effectively during the crisis. It is a country which shares a long land border with Syria and had previously been on exceptionally good terms with President Bashar al-Assad, helped by its exporters' domination of the Syrian market before 2011 and the Turkish goods that fill shops throughout the country.

Here was Ankara's first serious test as a regional power: it is a test that it has so far failed. But any future resolution of the crisis must involve Turkey, as the only one of Syria's immediate neighbours capable of exerting influence.

At the start of the popular uprising 15 months ago, the Turkish government appeared well-positioned to act as a conduit between the Syrian government and the opposition. Sadly, Prime Minister Tayyip Recep Erdogan set too much store by the laudatory press clippings about the rise of "the new Ottomans" and exaggerated his government's influence in Damascus.

When Ankara discovered that Mr Assad was stringing them along, without any intention of implementing their proposals for reform, warm relations between the two countries turned ice-cold over night.

But for all the talk of establishing a "safe haven" for refugees on the Syrian side of the Turkish border, it never happened, most likely thanks to the combination of threats from Iran and a desire to avoid the risk of war with Syria. Ankara would also be conscious that, until 2000, Syria was the main supporter and base for the Turkish Kurd guerrillas – the PKK – and Damascus could unleash these once again.

It would have been preferable if Turkey had not broken so wholly with the Syrian regime. As a result of Mr Erdogan's mis-playing of his cards, it is not the Turks but the Russians who have ended up as the one country with pivotal influence in Damascus. But there is still time to take back the initiative. And if there is to be regional action, it would be better led by Turkey than Saudi Arabia and Qatar – not least to avoid the absurd hypocrisy of pretending that two of the last absolute monarchies on earth are trying to overthrow Mr Assad because of their concern for the democratic and civil rights of the Syrian people.

It will be difficult at this stage to ease the Syrian regime out of power, and the prospect facing the world is rather of a prolonged guerrilla war, with alarming regional implications, that still may not produce a conclusive winner. International military involvement, or even just arming the rebels, have little to recommend them, even in the unlikely event that Russia could be brought on board. But there is much else that the international community can do, including the establishment of humanitarian corridors to ease the appalling suffering of Syria's civilian population. It is up to Ankara to take a lead.