What will it take to stop Turkeys slide into Islamism?

Another Mustafa Kemal Ataturk, which is not on the horizon.

It being a secular state - which it is. The people choose to follow Islam (for the most part) and that is their choice, just like the majority of Americans choose to follow Christianity.

At this point erdogan is getting more and more unpopular, and he doesnt have the power to keep the people in fear like Putin. So he will go out soon. The only reason the coup failed is because the only thing people hate more than erdogan is another junta.

Nothing can stop the Islamization of Turkey. Ultimately the Western Countries and Russia will have to kill them all.

Erdogan having a heart attack or some other debilitating medical condition.

When religious muslims stop trying to force everyone to convert to their religion

Nuclear winter.