The intentions of those peddling this narrative vary widely, and it's not the author's purpose to speculate on what's behind their joyful glee now that their dire anti-Syrian "prediction" has supposedly come to pass. Instead, it's much more constructive to examine what's wrong with this narrative and prove how categorically false it really is, with the tangential hope that this solid refutation will allow objective observers to identity the alternative and social media personalities which have "jumped the gun" on this whole episode and may have inadvertently revealed their true biases as a result.
Before proceeding, the reader should be reminded that the trilateral relationship between Russia, Turkey, and Iran has been flimsy from the get-go, owing mostly to the fact that it had been historically unprecedented until the first efforts were made at forming the Tripartite this summer (and which the author has thenceforth written about in a book-length article series for Katehon). There's always a chance that Erdogan really is as nefarious as his most virulent detractors claim that he is, and that a betrayal of Russia and Iran might indeed be imminent, but for now at least, that hasn't happened, and here's why.
For all of their stated political differences over the fate of democratically elected and legitimate President Assad, Russia and Iran have been on the same page as Turkey over everything else since this summer's failed pro-American coup attempt. President Putin and Erdogan already had two in-person meetings and several phone calls with one another, the Balkan Stream project is back online, and the decision has been made to normalize trade relations once more. In many ways, it's almost as if the tragic November 2015 shooting down of the Russian anti-terrorist jet over Syria hadn't happened, or if anything, that the relationship between both sides is now stronger as a result of having overcome that historically challenging period of high-level bilateral tensions. The martyrdom of Russia's treacherously murdered pilot will never be forgotten, but it optimistically appears as though the ultimate sacrifice of Lieutenant Colonel Oleg Peshkov is serving as the cornerstone for a sincere attempt by both sides to pioneer a new era in their Great Power relations.
As for Iran, the Islamic Republic has never been closer to Turkey than it is today. Foreign Minister Mohammad Zarif reminded the world on several occasions that his government was the first one to stand by Erdogan during the clumsy coup attempt, a fact which Tehran is evidently very proud of repeating. Iran's public exclamations of support for what Zarif at one time even termed "Turkish democracy" come despite hundreds of Iranian martyrs meeting their fateful ends at the hands of Turkish-backed terrorists in Syria, demonstrating just how serious Tehran must be about its friendly initiatives towards Ankara if it's willing to move beyond its own people's physical sacrifices, which are literally hundreds of times more numerous than Russia's. Part of what's motivating Iran is that it envisions one day connecting its North Pars gas field to the EU by means of an extension branch to the TAP pipeline which will one day transit through Turkey, and the other reason pushing it in the direction of strategic rapprochement with Turkey is for both Great Powers to coordinate their campaigns against cross-border Kurdish terrorists - the anti-Ankara PKK and anti-Tehran Kurdish Democratic Party of Iran (KDPI), respectively.
The strongest overlap of strategic commonality between Russia and Iran vis-a-vis Turkey is that Moscow and Tehran were both very receptive to Ankara's pre-coup signals of distancing itself from the US over Washington's support for the YPG and completely recalibrating its policy towards Syria as a result. For all of the other aforementioned resultant benefits that Russia and Iran aspire to receive from their new policies towards Turkey, it is Ankara's moves away from the unipolar US and towards the multipolar Eurasian World Order which matter the most, particularly because these can facilitate the salvation of their beloved Syrian ally.
It needs to be repeated over and over again that Russia and Iran's support for Syria is unwavering and non-negotiable, and that no amount of pipeline deals or anti-terrorist cooperation can be used to "buy them out", as their complementary policies towards Damascus are driven by concrete geostratgic principles which work out to their supreme self-interests. Nothing can override the unchanging geopolitical facts which underpin their commitments to Syria, which is why anybody alleging that any of these countries has "sold out" either doesn't have a mature enough understanding about the situation to be publicly commenting on it or might perhaps have deeper ulterior motives depending on their professional stature.
Proponents of the "sell-out" or "tricked" theory point to Turkey's military operation in northern Syria as either evidence of Russia and Iran's naive incompetence at foreign affairs for having been duped by Erdogan into going along with it, or as the smoking gun that they scandalously betrayed Damascus. Neither of these is true, as I argued in my two previous Katehon articles about "Turkey Crosses Into Syria: Unipolar Conspiracy Or Multipolar Coordination?" and "Turkey In Syria, The FSA, And The Upcoming Quarrel Over Syria's Constitution", which should be reviewed if the reader hasn't done so already in order to get the gist of the author's arguments apropos of this complex operation. The main point being proposed is that Russia and Iran - as Syria's loyal protectors - wouldn't allow Turkey to conventionally "invade" Syria if this was indeed Erdogan's intent, and that all related sides had likely reached some sort of agreement about this in advance, though are compelled by strong domestic public opinion to officially say the opposite. There is always the chance that Turkey will deliberately overstep its predetermined boundaries or outright betray its new "partners" (and this was touched upon in one of the articles), but like it was written before, this happened yet.
Observers should assess the situation surrounding Turkey's military operation in northern Syria in as much of an emotionally disconnected way as possible. The optics of the operation evoke very strong feelings among those who truly believe that Turkey is up to no good and is doing all that it can to take advantage of Russia and Iran's "naiveté", pointing to Syria's repeated public statements condemning Erdogan's actions. However, looking more carefully at what's happening, it begins to be clear that Turkey's conventional forces are mostly engaged in a "Lead From Behind" campaign to support its allied FSA proxies, in pursuit of the complicated post-Daesh multilateral political arrangement analyzed in the aforementioned Katehon article about Syria's Constitution. Erdogan obviously is hesitant about committing too many forces to northern Syria and would prefer for his government's allied non-state-actors on the ground to do the bulk of the fighting if he can help it (aside from staged photo-ops and other public relations ploys).
If he really intended to "invade" Syria with the purpose of "toppling Assad", it should be obvious to all non-biased observers that the second-largest military in NATO would likely have dispatched many more forces than it presently has. For a "regime change invasion" - if one is to take Erdogan by his words - the Turkish operation in northern Syria is miserably underperforming and has only "succeeded" in capturing a handful of towns from the YPG and Daesh (the latter of which mostly just melted into the "civilian populace" and/or shaved their beards and joined the FSA). Over a quarter of a year after it began, Turkey has nothing substantial to show for its efforts to "overthrow Assad", nor would it even be able to had it genuinely tried because Russia and Iran would have mobilized to stop it together with the Syrian Arab Army (and still will if they're compelled to).
This draws into question the entire purpose of Erdogan's recent "regime change" boast since it's proven that he clearly wasn't serious about seeing that new objective through. Furthermore, when he first sent troops to northern Syria, Erdogan said that this was for "anti-terrorist" reasons in stopping the YPG from setting up a rogue state along Turkey's southern borderland, and the Turkish government had hitherto maintained this stance up until now. Erdogan publicly changed his mind on this, however, in order to promote a few other objectives, none of which is actually aimed at "overthrowing" President Assad.
In any order, the first that can be discussed is that he wants to strengthen public opinion in advance of the forthcoming constitutional referendum that his government is planning in order to further centralize the president's control over the country. Judging by the last elections, Erdogan knows that he needs the support of the MHP nationalists for his proposal to pass, hence why he's pandering to them by changing the rhetoric behind why Turkey is in northern Syria. The next reason is closely tied in with the first one and relates to the amazing progress that the Syrian Arab Army and its patriotic militia allies have made in liberating most of East Aleppo. Erdogan is forced to react to this game-changing development, and given that any substantial action in the direction of "regime change" could lead to a devastating trilateral coalition response from Syria, Russia, and Iran, he's left with only empty words to shout in an unconvincing attempt to "save face". Finally, the last main reason behind why Erdogan is now all of a sudden repurposing the Turkish operation in northern Syria from being an "anti-terrorist" mission to a "regime change" one is because he wants to get on President-elect Trump's "good side" by showing that he hasn't completely "abandoned" the West (nor ever will, for that matter), despite recently revealing that he spoke with Russia and Kazakhstan about Turkey's prospective membership in the SCO.
Comment: Hard to say how that would get Erdogan on Trump's good side - Trump has said regime change is a bad idea. If anything, this would be a call to the deep state that still wants Assad to go.
In closing, Erdogan's inflammatory words about dispatching Turkish troops to Syria in order to "topple" President Assad should - like most of what he says - not necessarily he taken at face value, but instead be looked at for what they are, which is just the latest example of a long pattern of saying whatever he finds to be momentarily expedient for his given (usually undisclosed) agenda.
Rather than obsessing over every word that he utters and falling for the "confirmation bias" that so many people have, observers should be realistic and look at Turkey's actions, both in Syria and as regards its Tripartite partners of Russia and Iran, in order to get a more accurate picture of what's really happening. Ultimately, however, many individuals need to get past their greatest "confirmation bias", which is trying to find "evidence" in everything no matter what it may be that Russia and Iran either have "criminally incompetent" leaderships and/or "sold out" their trusted allies.
If these people remain consistent with their obvious innuendo, then one would be led to believe that Russia and Iran "allowed" Turkey to "invade" northern Syria for the purpose of "regime change" in exchange for pipeline deals and anti-terrorist cooperation, and that they've been "conspiring" with Turkey for over a quarter of a year now since Erdogan's operation first commenced. It's not to say that the Turkish strongman won't ever betray his new partners, but just that he hasn't done so yet (which is the operative point), and just because he deceived a few obnoxious Facebookers and alternative media commentators, doesn't mean that he "tricked" the much more experienced President Putin and the Ayatollah.