First, the good news. After months of dithering, the Turkish president Recep Tayyip Erdogan has given his approval for America to use the Incirlik air base in southern Turkey to mount air strikes against Islamic State (Isil) positions across the border in Syria.
Nearly a year after coalition planes began bombing Isil forces in Syria and Iraq, there is already much excitement being expressed in Washington that the Turkish decision could prove to be a game-changer in the campaign to defeat the Islamist menace. It will allow coalition forces to monitor more closely Turkey’s 500-mile border with Syria, which has been the main conduit through which Isil has smuggled arms and recruits, as well as enabling American warplanes to respond more quickly against likely Isil targets.
The bad news, though, is that the Turks’ decision has been somewhat undermined by Ankara’s renewal of hostilities against its long-standing foe, the Syrian Kurds.
The Syrian conflict is complicated enough without the Turks confusing matters even more by opening up another front against the Kurds, the majority of whom are seen as vital allies of the West.
On one side you have the Assad regime desperately trying to cling to power with the help of their allies in Tehran and the Iranian-backed Hizbollah militia in southern Lebanon. On the other, you have an estimated 1,200 Syrian opposition groups trying to lay claim to Damascus, with Isil and other more moderate ones, such as the Syrian Free Army, leading the charge.
Amid this chaotic landscape, the Syrian Kurds are one of the few combatant groups that have proved themselves to be heroic allies of the West’s cause. Backed by American air strikes, the Kurds fought valiantly to reclaim the strategically important border town of Kobani after it had been captured by Isil last year, one of the few high points for the West in a campaign that has otherwise failed to impress.
So the fact that Turkish planes are now bombing Kurdish positions in Syria, as well as those belonging to Isil, is counter-productive to the coalition effort, to say the least. In their defence, the Turks say they are only attacking positions held by the Kurdistan Workers’ Party, or PKK, an extreme nationalist group that has a long history of committing acts of terrorism against Turkish citizens, as a result of which it is officially designated a terrorist organisation by a number of states and organisations, including the US and Nato.
Before the Syrian civil war erupted four years ago, the PKK enjoyed the active support of the Assad regime, so much so that on several occasions Syria and Turkey came close to hostilities.
This bad blood was one of the reasons that Mr Erdogan aligned himself with the struggle to overthrow the Assad regime, an alliance that has prompted accusations that Ankara has colluded with Isil militants in Iraq.
The Turks’ ambivalent relationship with Isil, as well as their insistence that the coalition should concentrate its efforts should on removing Assad, have been the main stumbling blocks to closer cooperation between Ankara and the US.
Now, so far as Ankara’s dealings with Isil are concerned, the Turks are paying a heavy price for their double standards. The Isil suicide bomb attack against the border town of Suruc this month, in which 32 people were killed and 100 injured, has finally persuaded Mr Erdogan’s government that Isil poses just as great a threat to Turkey’s security as it does to the rest of the region.
But if the Suruc bombing, together with a number of other Isil cross-border attacks against the Turkish military, has been the catalyst for Mr Erdogan’s change of heart, the Turks’ obsession with the Kurds means they are still a long way from becoming reliable allies.
As James Clapper, the US director of intelligence, notably remarked during a recent briefing to Congress, Turkey has “other priorities and other interests” so far as the Syrian conflict is concerned.
Mr Erdogan’s determination to confront the Kurds, moreover, has deepened as a result of the strong showing by the moderate Kurdish People’s Democratic Party (HDP) in last month’s parliamentary elections, which dealt the president a severe blow as his Justice and Development Party (AKP) lost its overall majority for the first time in more than a decade.
Mr Erdogan is desperate to regain ground against the Kurds, and many opposition politicians see his sudden enthusiasm for reopening hostilities with the PKK as a clumsy attempt to portray Kurds – be they Turkish, Syrian or Iraq – as being sympathetic to the PKK’s terrorist agenda.
The tactic may help Mr Erdogan to regain his parliamentary majority, but it will do nothing to assist the coalition war effort against Isil.
What Mr Erdogan needs to understand it that, even if the Turks disown Isil, they cannot bomb the Kurds and still be considered dependable allies.
Syrian/Turkish relations: A timeline
Turkey is being dragged further into the four-year conflict in neighbouring Syria following a deadly suicide attack, blamed on Isil, that killed 32 activists near the border.
September 13, 2011
«The Syrian people do not believe al-Assad, I do not either,» says Recep Tayyip Erdogan, then premier, a few months after calling the Syrian leader his «friend». Mr Erdogan warns of civil war in Syria.
October 2, 2011
Following a series of meetings in several Turkish cities, Syrian opposition leaders announce the creation of the Syrian National Council (SNC), which groups political factions opposed to the Assad regime.
November 15, 2011
Turkey passes its first sanctions against Syria, and halts joint oil exploration with the country.
June 22, 2012
A Turkish plane that Ankara says was on a training mission in international airspace is shot down by Syrian forces.
May 11, 2013
Twin attacks kill 52 people in Reyhanli, a large Turkish town near the border with Syria.
September 16, 2014
Isil militants attack the Syrian border town of Kobane, and seize parts of it. Kobane becomes the scene of fierce battles.
May 16, 2015
Turkey says it has shot down a Syrian helicopter that violated its airspace.
July 20, 2015
At least 32 people die when a suspected Isil suicide bomber attacks a gathering of activists in the town of Suruc, near the Syrian/Turkish border.
July 22, 2015
The Kurdistan Workers’ Party (PKK) claims the killing of two Turkish policemen in the border town of Ceylanpinar in revenge for the Suruc massacre.A government spokesman denounces the murders as «a terrorist act perpetrated by a terrorist organisation.»
July 23, 2015
Jihadists inside Syria open fire on a Turkish army border post in the Kilis region, killing a non-commissioned officer and wounding two soldiers. In Diyarbakir, a majority Kurdish city in south-eastern Turkey, gunmen kill a Turkish policeman and seriously wound another.
July 24, 2015
Turkish F-16 jets hit Isil targets just inside Syria for the first time, killing nine Isil militants. Late in the day, airstrikes also target PKK militants in northern Iraq.
July 25, 2015
Turkish air strikes intensify against Isil jihadists in Syria and PKK militants in Iraq.
July 26, 2015
Ankara launches F-16 attacks for the third day, striking Kurdish command posts in northern Iraq. Turkish protesters battle security forces in Istanbul, a policeman is shot and killed. Turkey asks for an extraordinary Nato meeting to discuss its cross-border offensive, but has not asked for help, the group’s chief says.
July 27, 2015
Turkish tanks pound a Kurdish-held village in northern Syria, wounding at least four fighters and several villagers, Kurdish groups and a Syrian monitor say, while a Turkish official maintains the army is not targeting Syrian Kurds.
Con Coughlin is an expert on international terrorism and the Middle East; with the benefit of 25 years in foreign journalism, he deftly scrutinises world affairs.