Terraform state isolation starts before terraform plan ever runs.
This lesson explains why backend configuration belongs to the initialization phase and why Terraform variables cannot dynamically select backend destinations. The video walks through separate backend files for dev and prod environments, S3 state paths, runtime environment variables, and lightweight AWS resource evidence using SSM Parameter Store.
The operational focus is environment isolation. One shared backend can combine unrelated infrastructure into a single failure domain. Separate backend addresses create a hard boundary between dev and prod state mutations.