Resources don't seem to show up in Terraform state after import
I figured it out. The stub resource has to have a provider that is configured with the proper AWS region. All these security groups were in us-west-2. You need this:
resource &quot;aws_security_group&quot; &quot;rds-launch-wizard-2&quot; { provider = aws.us_west_2 }

instead of this:
resource &quot;aws_security_group&quot; &quot;rds-launch-wizard-2&quot; {}

This assumes you have a provider already configured thus:
provider &quot;aws&quot; {
  region  = &quot;us-west-2&quot;
  alias   = &quot;us_west_2&quot;
}