All the pieces are in place for a major Syrian regime offensive to retake Idlib in northern Syria from rebels and extremist groups that have held it for years. Ankara is now scrambling to prevent a disaster in Idlib, while the UN has proposed humanitarian corridors for civilians to flee. As the US warns of an escalation in an “already dangerous conflict,” Russia has said it is time to defeat the “hotbed of terrorists.” There are thought to be millions of people who will be at risk in Idlib when the offensive begins, and at least 10,000 fighters associated with Hayat Tahrir al-Sham (HTS), the main Syrian group in Idlib that was previously affiliated with al-Qaeda.Behind all the rhetoric is a more complex process of three major regional states and their local allies posturing to resolve the Idlib crisis. Turkish President Recep Tayip Erdogan is scheduled on September 7 to go to Tehran, where he will meet Russian President Vladimir Putin and Iranian President Hassan Rouhani.Meanwhile, Russia has sent 26 warships and submarines into the Mediterranean off the coast of Syria where it claims it will conduct military drills from September 1-8, coincidentally just as the Idlib crisis heats up. According to Russian sources, the ships include missile cruisers that carry cruise missiles and TU-160 strategic bombers.Syria has already dropped leaflets over Idlib warning of the upcoming offensive and has sought to encourage villages and towns to accept “reconciliation” with the Syrian regime, rather than resist. In addition, Moscow, Hezbollah and pro-regime sources have all warned that there is a “false flag” chemical-weapons plot being prepared in Idlib to lure Western powers to carry out air strikes on Damascus.Not so long ago Turkey looked set to stay in Idlib province. Since 2016, Turkey has increased its involvement in Syria. First it rolled into Jarabulus to carve out an area along the border designed to thwart US-backed Kurdish forces from linking up with colleagues in Afrin. Then it sent forces into parts of Idlib and established a dozen observation points overlooking areas held by the Syrian regime. In January it attacked Afrin, which was held by the Kurdish People’s Protection Units at the time, and took over Afrin along with its Syrian rebel allies.Turkey played a role in Idlib during this time. In February 2018, an article in Hurriyet revealed that HTS members had even been “accompanying” a Turkish military convoy there. But on Friday, Turkey declared HTS a terrorist organization. This will isolate HTS and, in theory, force it to break any links with Turkish-backed rebel groups.Meanwhile, Ankara is seeking to prevent a major military campaign “to prevent another Aleppo-like disaster.” Turkey’s foreign minister went to Moscow while Iran’s foreign minister went to Ankara for discussions. If an offensive starts, it could have “very serious problems from the humanitarian, security and political settlement perspectives,” Turkish Foreign Minister Mevlut Cavusoglu said on Friday. Turkey’s main concern in idlib is that millions of refugees will flee and Ankara will be seen as having abandoned Idlib. Turkey has generally been sympathetic to the Syrian rebel cause since 2011, and has hosted three million Syrians. That is why Turkey wants to use diplomacy to stop the offensive. But at the same time, Turkey’s economy is reeling as a result of a dispute with the US and Ankara has been drawing closer to Moscow. It recently inked a deal to purchase two Russian S-400 air defense systems. As the Syrian regime’s main backer, Moscow is now able to broker whatever deal it wants because Ankara needs Moscow more than Russia needs Turkey.What does Moscow want? Foreign Minister Sergey Lavrov said on Friday that Damascus has a right to “chase terrorists out of Idlib.” He calls the province a “hotbed of terrorists” and said that inaction does not bode well. But Russia also wants a quick operation to defeat HTS. Russia and Syria appear to have gained some support from the UN. Speaking in Geneva on August 30, UN Syria envoy Staffan de Mistura indicated that there were 10,000 fighters the UN has designated as terrorists. He also said, “We are aware that both the government and al-Nusra [HTS] have the capability to produce weaponized chlorine.” This seems to mean that even the UN thinks there is a chance HTS could perpetrate its own chemical weapons attack. This is the “false flag” that Russian sources have spoken of, a chemical attack in which the regime is blamed, but which HTS has carried it out.HTS and its supporters have blown up bridges and are digging trenches in preparation for the final battle. They are asking residents to take up arms as HTS poses as the sole independent defender of Syrians who support the rebellion against Assad. But Damascus is confident it will win, with Syrian Foreign Minister Walid Muallem bragging that the “Americans lost militarily in Syria” and asserting that Syria would soon retake the rest of the country from areas under opposition and foreign control.So how will the offensive unfold? The Syrian regime wants it to be quick, with overwhelming force and not too many casualties. Pressure will mount on Turkey if refugees flee. Chemical attacks could lead to US air strikes. But those air strikes will be made more complex by the presence of a massive Russian fleet that has warned its drills are “dangerous for air traffic” in the area. The Syrian regime hopes Russia has already brokered a deal with Ankara to allow it to crush HTS and divide Idlib, such that Turkey will likely retain some influence with existing rebel factions that it supports as HTS is dismantled. This could all go smoothly. It is Moscow’s ability to actually broker the division of Idlib that is being tested. Moscow tested its abilities to broker cease-fires in southern Syria in July. Now it has a bigger challenge.