I have not been terribly motivated to write anything about the upcoming 1 November elections, because I actually find that there is very little that I can add to the discussion. Why? First, because Turkish politics has become so deeply polarized. Second, because some of the most important questions surrounding this election have nothing to do with how people vote.
But here are some important points about this election, which provide insight into what I think will happens.
1. Party support remains (virtually) unchanged
Both theory and (polling) evidence suggest that the underlying levels of support for each party remain about the same as on 7 June. Basically, AKP remain stuck around 40-43%, CHP at 25-28%, MHP at around 13-16%, and HDP at around 11-14%.
Why? My rhetorical question to anybody who is asking this question is: "what has changed?" That might sound stupid after Suruc, the renewed conflict with PKK, the Ankara bombings, arrests of HDP officials, etc. But let me phrase my rhetorical question more clearly: "which group of voters who voted for AKP would be persuaded by the events since 7 June to switch their vote to the opposition, or vice versa?"
Since AKP reached its high water mark during the 2011 parliamentary elections, party support in Turkey has become more polarized with members of various groups that previously supported AKP at least in part abandoning it (e.g., 'liberals,' conservative Kurds, Gulenists). But that had all happened by 7 June; HDP's rise above the 10% threshold was the last part of that process. If one still supported AKP on 7 June, it's hard to see how subsequent events would have destroyed that support (in any systematic fashion that would matter to an election result).
Instead, everything that has happened since 7 June has reinforced the divisions and distrust between AKP and the opposition parties. The result has been very little transfer of support between AKP and the opposition parties.
2. Changes that (don't) matter
There may be some change in support between the three opposition parties. Possibly, CHP has gained support from either (or both) MHP and HDP. Obviously, though, this won't have much effect on the 'big picture' (unless everything conspires to drop HDP under 10%). Even with some shift between opposition parties, AKP would still end up with a vote share between 40-43% and a plurality of parliamentary seats.
Similarly, rumors of a breakaway 'fifth party' from AKP won't matter for this election.
3. The Turnout Factor
This is always the under-examined question. So what should we expect?
On the positive side, this election fits the criteria for a high-turnout election. The stakes of the election are high: Erdogan's presidential vision versus opposition hopes to restrain his power. And the choice is clear: a vote for AKP is a vote for Erdogan, while a vote for the opposition is a vote against it. And the potential outcome is clear in one sense: if AKP get a majority, then Turkey will be at least a de facto 'presidential' system until 2019.
On the negative side, this is now the fourth election in Turkey since March 2014. At some point, voter fatigue becomes an issue. In addition, each party has to spend resources to mobilize its voters, and these are finite. It is also occurring at the end of a long holiday weekend, which might tempt voters to go on vacation and be unable to vote.
My sense is that the importance of the election will outweigh the fatigue and vacation factors, and turnout will be high again.
However, differential turnout may be crucial: if, for example, a disproportionately high number of CHP supporters go on holiday and miss the vote, then it will suffer relative to the other parties.
4. Free and fair?
This is arguably the biggest question in this election. There are two senses in which this election may not be free and fair.
First, there is the general environment in which this election takes place. I have argued elsewhere that Turkey is best understood at present as a case of competitive authoritarianism, though others might call it an illiberal democracy. Regardless, the 'playing field' in Turkey is heavily tilted toward AKP. Its use of state resources to mobilize voters is well-known. So is its efforts to create a restrictive media environment that only provides pro-government coverage. To add to that, opposition leaders and buildings (particularly of the HDP) have been targets of arrest and mob violence. All of this creates a generally unfair competition, in which AKP have structural advantages in the election. Of course, this was true on 7 June as well, so this claim is perhaps more of a constant than a variable.
Second, there is the question of what will happen on election day, as people vote, as the votes are counted, and as the results are reported. The stories from recent elections are well-known to observers of Turkish politics: the mysterious power outages as votes are being counted and recorded, the apparent cyber-attacks on opposition-friendly news sites, stories of extra pre-stamped ballots, of ballots being destroyed, and of inconsistencies in vote counts at various stages of the process. On 7 June, there were also the mysterious unmarked cars at many voting locations, though it was unclear what that was about. All of that, and possibly some new schemes, could occur again on 1 November. Of course, the opposition parties and civil society groups such as Oy ve Otesi will work hard to prevent election fraud. In this respect, recent pro-government media campaigns against Oy ve Otesi are worrying, as it might suggest the prelude to a campaign to arrest their volunteers en masse on election day.
This election has another disturbing feature: the ongoing conflict with PKK in the southeast of Turkey. Since July, various areas have been placed under curfew and/or declared special security zones. There is a heavy police and military presence in the area. As the government appoints the governors of each region, they have the power to implements various curfews or states of emergency. There have also been proposals to relocate or consolidate voting locations, which have generated opposition concerns about vote suppression. As the Kurdish-heavy southeast is expected to vote in large number for HDP, the problem is easy to see.
I have no special insight into what AKP or Erdogan might have planned. You can believe as much or as little of what 'insiders' like the infamous Twitter account Fuat Avni claim. As a political scientist, I can point out the following. First, AKP have the motive and opportunity to commit election fraud. Second, elections in countries like Turkey have experienced fraud in these conditions (and it seems very likely that recent Turkish elections have, as well).
Some observers claim that this just doesn't happen in Turkey. I am personally unconvinced by cultural-style arguments suggesting that elections are too 'sacred' to Turks to be subjected to fraud. Has anything we've seen about Erdogan and certain other AKP leaders really let us believe that he would let a little morality get in the way? Given Erdogan's stated ambitions and the present reality, electoral fraud would be a rational strategy. So my conclusion is that there is good reason to expect attempted electoral fraud, but it may or may not be successful.
Regardless, we should not lose sight of the 'big picture' ways in which this is already not a fair election.
Given the uncertainty created by point #4, it seems hard to offer a clear prediction. So I will say this: if the election is held fairly, it will produce a result similar to that of 7 June. In other words, AKP will win the election with slightly over 40% of the vote and somewhere around 250-270 seats in parliament (shy of a majority). And, importantly, HDP will stay above 10% and in parliament.
I realize this contains an element of non-falsifiability: any result that deviates from my prediction must be the result of fraud, right? Well, no...we must be able to point to real evidence of fraud actually occurring--eyewitness accounts, inconsistencies that can't be explained by random error, or the like.
There is also the question of what will happen after the election is done. Regardless, it promises to be turbulent, as Erdogan will surely continue in his ways while the opposition is unlikely to give ground.